About your different discussion, I have to tell you that you are right, there are PP involved, even with the 5:1 trivial combat rule. As you said, it is simply to avoid to choose a chit since there is no sense in such a proportion of troops.
And there is always a lost of PP since there are corps involved in the fight, that is the basic rule, corps involved in a combat, PPs won/lost.
that is the way i have always understood it, but i have played in several pbem games where the majority felt otherwise, so when a vote was taken we ended up playing that the rule meant 5:1 combats were not worth pps - which just led to people attacking screens with 4-factor corps then reinforcing in, it was silly.
there are several (dozens) of rules that i've learned that people play different ways, i ended up keeping a list of them all, and each new pbem game with new players, i would list them all and we'd vote on them. That way whether we agreed or not, we all knew how we were playing the rules - it made for far less arguments