At least one of the Hetzers was a cannon knock out; the other one may have been a cannon shot but the 4 rocket craters in close proximity may have been involved.
I was actually keeping brief notes on the game, so I logged the attacks "real time" or "replay time". There were definitely 7 continuous attacks, 4 of which were rocket ones.
I didn't think the Typhoon had 16 rockets, I thought it was 8, but that would explain a lot.
I still wouldn't buy aircraft myself, but if you are the British it must be a temptation to load yourself with Churchill Mk VIIIs and bung in a fighter to upset any big German tanks. In a very non-gamey way, obviouly.