At least in the first case you're correct.
Winning on the German side is rare, unless it's very upstrengthened and manage to take out all Shermans before losing the StuGs. Otherwise the Germans may hold on to the ridge but achieve little more.
I've only started playing the Siegfried line, and been pretty beaten up (as American) in the first two turns... :-(
(The 105mm gun seems useless against concrete bunkers.)
Cheers
Olle