diff --git a/crates/helm-bv/UPSTREAM.md b/crates/helm-bv/UPSTREAM.md
index ba00815..407e967 100644
--- a/crates/helm-bv/UPSTREAM.md
+++ b/crates/helm-bv/UPSTREAM.md
@@ -120,3 +120,41 @@ rules; correcting it upstream would change those five battle values.
 `slot < entity.locations()`, which is the number of locations rather than the
 number of critical slots in one. A Mek arm has twelve slots and the loop
 checks eight, so a blade mounted low in an arm is not found at all.
+
+## An IndustrialMek that is not ICE-powered still generates movement heat
+
+TechManual gives the heat efficiency of a Mek as `6 + heat sink capacity -
+movement heat`, and says that *ICE-powered* IndustrialMeks generate no heat
+when moving and so have a movement heat of 0. MegaMek gives 0 to every
+IndustrialMek, whatever drives it, and helm reproduces that.
+
+The book's own worked example is the disagreement: a WI-DM DemolitionMech has
+a Fuel Cell engine rather than an ICE, and the example computes
+`6 + 1 - 2 = 5`, charging it the two points for running. MegaMek and helm both
+make it 7.
+
+104 of the 180 IndustrialMeks in 0.51.0 are not ICE-powered, so this is not a
+one-design curiosity - but it cannot change an answer in practice. An
+IndustrialMek gets ten free heat sinks and rarely carries enough weaponry to
+generate ten points of heat, so its total weapon heat sits below both figures
+and the budget never binds. It would take a design whose heat falls between
+the two, and the library has none.
+
+Recorded rather than fixed, because conformance here is with MegaMek. If
+MegaMek changes, helm follows, and this note is what will explain why the
+answers moved.
+
+## The Watchdog's offensive value is unreachable
+
+`BVCalculator.processOffensiveEquipment` skips `F_ECM` equipment unless it is
+also `F_WATCHDOG`, and further down sets `bv = 7` for a Watchdog - an
+exception written to let one ECM suite through and score it. It never runs.
+
+The same condition that lets the Watchdog past the `F_ECM` test also skips
+anything whose `offensiveEquipmentBV` is zero, and a Watchdog's is. The
+exception is dead code.
+
+helm reproduces the behaviour rather than the intent: scoring the Watchdog at
+7 as written costs twenty-one designs. Whether the intent or the behaviour is
+right is a question for MegaMek; the answers are what conformance is measured
+against, so the answers are what helm follows.