diff --git a/goodwe_controller/DECISIONS/OPT-11-battery-modes.md b/goodwe_controller/DECISIONS/OPT-11-battery-modes.md
index b5d970c..5a68ede 100644
--- a/goodwe_controller/DECISIONS/OPT-11-battery-modes.md
+++ b/goodwe_controller/DECISIONS/OPT-11-battery-modes.md
@@ -114,5 +114,9 @@ P1 is its section 6 P1, and the pull request lists what was measured.
   - the days' real 2026 quarter-hourly prices (held out): P2 32.26, option A
     32.01, old trade 31.40, P4 29.19 (perfect 29.21, too high 29.28, missing
     32.01).
+  - Solar first + Cheap hours only: 19.57 on both P3 and P4 (year-earlier
+    prices); on real 2026 prices P4 29.72 against P3's 29.41. Skipping the
+    sun's share does not pay for Cheap hours there; Leftover solar is the
+    mode the forecast pays for.
   No threshold was tuned to these days. The 2026-09-24 PV recording could not
   be replayed: it is only in the live Home Assistant.
diff --git a/goodwe_controller/test_modes_p4.py b/goodwe_controller/test_modes_p4.py
index 7847e3c..74b5b2e 100644
--- a/goodwe_controller/test_modes_p4.py
+++ b/goodwe_controller/test_modes_p4.py
@@ -36,6 +36,7 @@ sys.path.insert(0, HERE)
 sys.path.insert(0, os.path.join(HERE, "tools"))
 logging.disable(logging.WARNING)
 
+from named_absence import nth, present                         # noqa: E402
 import opt11p3_replay as rp                                    # noqa: E402
 from app import arbitrage, dayplan, homeview, modetrade, packmode  # noqa
 from app import priceruns, solarfc, validate                    # noqa: E402
@@ -320,8 +321,21 @@ check("Cheap hours: dark fills to the ceiling (as P3)",
 check("...and skips the part the sun covers on a partly sunny day",
       ch.targets[B] < 95.0 and ch.share_kwh[B] > 0
       and abs(ch.targets[B] - (95.0 - ch.share_kwh[B] * 10.0)) < 0.01)
-check("trust 100 % counts more sun than 70 %: a lower or equal level",
-      dplan(12.0, trust=100).targets[B] <= partly.targets[B])
+check("trust 100 % counts more sun than 70 %: a lower level",
+      dplan(12.0, trust=100).targets[B] < partly.targets[B])
+check("...and the sun counted scales with the trust exactly",
+      abs(dplan(12.0, trust=100).sun_kwh * 0.7 - partly.sun_kwh) < 0.01)
+_room_a = (95.0 - 60.0) / 10.0 * 10.0 / 10.0     # A: 60 % -> 95 % of 10 kWh
+check("Solar first takes the sun first: B's share is what is left after "
+      f"A's {_room_a:.1f} kWh of room",
+      abs(partly.share_kwh[B] - max(0.0, partly.sun_kwh - _room_a)) < 0.01
+      and partly.share_kwh[B] < partly.sun_kwh)
+_flat = (lambda h: 600.0, 600.0)
+_sunny_net = (lambda h: -2000.0 if 9 <= h < 17 else 600.0, 600.0)
+check("the house's net use in sunny hours (negative) is lifted to the night "
+      "floor: the same sun as a flat 600 W house",
+      abs(dplan(12.0, est=_flat).sun_kwh - dplan(12.0, est=_sunny_net)
+          .sun_kwh) < 1e-6)
 check("no forecast, no house profile or no price plan: no plan",
       dayplan.plan(None, EST, R0, T0, PACKS, trust_pct=70, floor_pct=20,
                    ceiling_pct=95) is None
@@ -530,7 +544,8 @@ def invariants(tag, rows, c):
 # Sunny: 40 kWh forecast. B (Leftover solar) at 30 % needs nothing.
 rows, st_, c = run_day(SF_LS, fc=40.0, soc0={"a": 60.0, "b": 30.0})
 charge = invariants("sunny", rows, c)
-print(f"    sunny: verdict {rows[-1]['plan'] and rows[-1]['plan'].verdict}, "
+_last = nth(rows, -1, "a cycle")
+print(f"    sunny: verdict {present(_last) and _last['plan'] and _last['plan'].verdict}, "
       f"{len(charge)} charge cycles")
 check("sunny: a day plan is made, and says sunny",
       any(r["plan"] is not None and r["plan"].verdict == dayplan.SUNNY
@@ -540,7 +555,7 @@ check("sunny: no grid charge at all", not charge)
 # Dark: 1 kWh. B buys the evening's shortfall only, in the cheap run.
 rows, st_, c = run_day(SF_LS, fc=1.0, soc0={"a": 60.0, "b": 30.0})
 charge = invariants("dark", rows, c)
-tgt = next(r["targets"][B] for r in rows if r["targets"])
+tgt = nth([r["targets"][B] for r in rows if r["targets"]], 0, "a level")
 top = max(r["soc"]["b"] for r in rows)
 print(f"    dark: B level {tgt:.1f} %, B reached {top:.1f} %, "
       f"{len(charge)} charge cycles")
@@ -548,18 +563,18 @@ check("dark: Leftover solar charges from the grid in the cheap run",
       charge and all(r["runs"].cheap.holds(r["now"]) for r in charge)
       and all(r["roles"][B] == modetrade.CHARGE for r in charge))
 check("dark: ...only up to its level (the shortfall), not 95 %",
-      tgt < 60.0 and top <= tgt + 2.0)
+      present(tgt) and tgt < 60.0 and top <= tgt + 2.0)
 check("dark: A rests while B charges", all(r["roles"][A] == modetrade.REST
                                            for r in charge))
 
 # Cheap hours on a partly sunny day: skips the part the sun covers.
 rows, st_, c = run_day(SF_CH, fc=14.0, soc0={"a": 60.0, "b": 30.0})
 charge = invariants("cheap hours, partly", rows, c)
-tgt = next(r["targets"][B] for r in rows if r["targets"])
+tgt = nth([r["targets"][B] for r in rows if r["targets"]], 0, "a level")
 top = max(r["soc"]["b"] for r in rows)
 print(f"    cheap hours partly: B level {tgt:.1f} %, reached {top:.1f} %")
 check("Cheap hours with sun forecast: charges, but stops below 95 %",
-      charge and tgt < 90.0 and top <= tgt + 2.0)
+      charge and present(tgt) and tgt < 90.0 and top <= tgt + 2.0)
 rows_nf, _s, c_nf = run_day(SF_CH, fc=None, soc0={"a": 60.0, "b": 30.0})
 check("...and with the forecast down it fills towards 95 % as in P3",
       max(r["soc"]["b"] for r in rows_nf) > top + 10.0)
@@ -614,6 +629,30 @@ check("...while the profile learns and the store keeps each closed hour",
           c.store.data.get("house_profile") or {}) >= 1)
 check("selling stays off (option A)", packmode.SELLING_ENABLED is False)
 
+# A forecast arriving mid-period makes the plan at once, not at the next
+# 15-minute period.
+COME = datetime(2026, 9, 21, 1, 3, tzinfo=L).astimezone(timezone.utc)
+rows, st_, c = run_day(SF_LS, fc=lambda now: None if now < COME else 1.0,
+                       soc0={"a": 60.0, "b": 30.0}, hours=0.5)
+first = next((r["now"] for r in rows if r["targets"]), None)
+check("a forecast that arrives at 01:03 makes the plan before 01:15",
+      first is not None and first < COME + timedelta(minutes=3))
+
+# Battery modes off: the forecast is never read.
+READS = [0]
+_real_sensor = rp.Hass.state
+
+
+async def _counted(self, e):
+    READS[0] += 1
+    return await _real_sensor(self, e)
+rp.Hass.state = _counted
+FC_KWH[0] = 1.0
+rp.run("modes_off", house_flat(800.0), WPTS, UTC0 + timedelta(hours=1),
+       600.0, extra=dict(FC_OPTS))
+rp.Hass.state = _real_sensor
+check("battery modes off: the forecast sensor is never read", READS[0] == 0)
+
 # ============================================================================ #
 print("7. the Batteries screen and the Simple view")
 rows, st_, c = run_day(SF_LS, fc=1.0, soc0={"a": 60.0, "b": 30.0},
@@ -627,7 +666,22 @@ why = homeview.day_key(c, B)
 check("B's Why key (plan, dark) is tops_up", why == "tops_up")
 check("...and says so in plain words", homeview.why_words(why)
       == "Too little sun is forecast, so it charges some from the grid.")
+_d0, _d1 = homeview.local_day(c.solar_fc.at)
+_blocks, _ = homeview.mode_runs(c, _d0, _d1, c.solar_fc.at, False)
+_grid = [b for b in _blocks if b["kind"] == "grid" and b["battery"] == 1]
+_need = homeview.plan_need(c, B)
+check(f"Today: B's grid block is the planned shortfall ({_need:.2f} kWh), "
+      "not its room to 95 %", _grid and abs(_grid[0]["kwh"] - _need) < 0.01
+      and _need < 3.0)
+_run = c.mode_runs.cheap
+_packs = c._mode_packs()
+_m1 = c._run_mark("charge", _run, _packs, lambda p: True, ((B, 40.0),))
+_m2 = c._run_mark("charge", _run, _packs, lambda p: False, ((B, 50.0),))
+check("a level the hysteresis moved opens the run to that battery again",
+      _m1 and not _m2)
 c.solar_fc = None
+check("the levels are dropped as soon as the forecast goes, even before "
+      "the plan is rebuilt", c._plan_targets and c.plan_targets() is None)
 check("a lost forecast says so: no forecast, Leftover solar solar only",
       homeview.solar_block(c, datetime.now(timezone.utc))["state"]
       == "no_forecast" and homeview.day_key(c, B) == "no_forecast")