I suspect that the issue is the 4-Stacker, which did not enter RN service until after the Destroyer for Bases deal in 1940. If this is the case, then the presence of a 4-Stacker escort in the simulation where none could be in real life is an intolerable, game-breaking bug.
All modders and developers responsible for this egregious abuse of history should be shot at dawn and SH4 GWX3 must be removed from every computer in the world with immediate effect.
This horrific Crime Against Realism must be stamped out of existence as it is an offence to rivet-counters everywhere.
-C