diff --git a/goodwe_controller/test_modes_p4.py b/goodwe_controller/test_modes_p4.py
index c308e57..957fa05 100644
--- a/goodwe_controller/test_modes_p4.py
+++ b/goodwe_controller/test_modes_p4.py
@@ -672,9 +672,24 @@ check("Cheap hours with a sun forecast charges as with none (P3)",
       and top > 80.0)
 
 # The forecast goes away mid-run: Leftover solar stops at once (P3 option A).
+# OPT-27: a sensor that is unavailable is covered by its last fresh reading
+# for up to 3 h (`solarfc.Hold`), so "lost" here is a hold that never covers;
+# the next scenario is the same loss with the hold (test_opt27.py).
 DROP = UTC0 + timedelta(hours=1, minutes=30)
+
+
+class _NoHold(solarfc.Hold):
+    def stand_in(self, *a, **k):
+        return None
+
+
+def seed_profile_no_hold(c):
+    seed_profile(c)
+    c.fc_hold = _NoHold()
+
+
 rows, st_, c = run_day(SF_LS, fc=lambda now: 1.0 if now < DROP else None,
-                       soc0={"a": 60.0, "b": 10.0})
+                       soc0={"a": 60.0, "b": 10.0}, patch=seed_profile_no_hold)
 invariants("forecast lost mid-run", rows, c)
 before = [r for r in rows if r["now"] < DROP and r["action"]
           == arbitrage.CHARGE]
@@ -682,6 +697,15 @@ late = [r for r in rows if r["now"] > DROP + timedelta(
     seconds=2 * 60 + 10) and r["action"] == arbitrage.CHARGE]
 check("forecast lost mid-run: Leftover solar was charging, and stops within "
       "a forecast read (60 s) and a cycle", before and not late)
+rows, st_, c = run_day(SF_LS, fc=lambda now: 1.0 if now < DROP else None,
+                       soc0={"a": 60.0, "b": 10.0})
+invariants("forecast unavailable mid-run, covered", rows, c)
+check("forecast unavailable mid-run (OPT-27): the last reading covers it, so "
+      "Leftover solar goes on charging past the point where it was lost",
+      [r for r in rows if r["now"] < DROP and r["action"]
+       == arbitrage.CHARGE]
+      and [r for r in rows if r["now"] > DROP + timedelta(
+          seconds=2 * 60 + 10) and r["action"] == arbitrage.CHARGE])
 
 # The forecast is far too high (40 kWh, and there is no sun at all): no grid
 # charge, so B covers less of the evening - a money risk, never a safety one.
diff --git a/goodwe_controller/test_opt27.py b/goodwe_controller/test_opt27.py
index fd28a8c..7f9cb0e 100644
--- a/goodwe_controller/test_opt27.py
+++ b/goodwe_controller/test_opt27.py
@@ -100,7 +100,7 @@ check("22:00 with the sensors stale since 17:05: the 17:05 figures are used",
       fc is not None and fc.kept and fc.tomorrow.kwh == 12.0
       and fc.at == D1_READ and gaps == ())
 check("... today has no sun left in it, tomorrow's is counted from 06:00",
-      fc.between(EVE, at(4, 7, 0)) is not None
+      fc is not None and fc.between(EVE, at(4, 7, 0)) is not None
       and 0.0 < fc.between(EVE, at(4, 7, 0)) < 0.5
       and fc.today.kwh == 0.4)
 fc2, _w, _g = rs(GONE, GONE, EVE, h)
@@ -146,12 +146,16 @@ check("02:59: tomorrow's 12.0 kWh is now today's, there is no tomorrow",
       fmid is not None and fmid.today.kwh == 12.0 and fmid.tomorrow is None
       and fmid.kept and fmid.today.day0 == at(4, 0, 0))
 check("... its sun is counted on the day it is for (06:00-20:00 on the 4th)",
-      fmid.between(at(4, 3, 0), at(4, 7, 0)) is not None
+      fmid is not None and fmid.between(at(4, 3, 0), at(4, 7, 0)) is not None
       and fmid.between(at(4, 3, 0), at(4, 7, 0)) > 0.0)
 check("03:01 (midnight + 3 h): not used any more",
       rs(GONE, GONE, at(4, 3, 1), h2)[0] is None)
 check("... and not the next evening either (older than one night)",
       rs(GONE, GONE, at(4, 22, 0), h2)[0] is None)
+fe = rs(st(0.1, at(4, 21, 50)), GONE, at(4, 22, 0), h2)[0]
+check("... the next evening, with today fresh and tomorrow's sensor down, "
+      "there is no tomorrow: the 4th's figure is not the 5th's",
+      fe is not None and fe.today.kwh == 0.1 and fe.tomorrow is None)
 # Never today's figure for tomorrow.
 h4 = solarfc.Hold()
 rs(st(3.0, at(3, 17, 0)), st(12.0, at(3, 17, 0)), at(3, 17, 5), h4)