i believe the SBR and rocket attacks says:  whichever is greater, but MAXIMUM of the IPC value of the attacked territory.  if the IPC value is 5, then they only pay 5 IPC’s max for that attack.

i just got the revised edition for my dad for christmas, we only played it 1x, so i’m just a beginner.  now, we DID play ‘minor victory’ and it still took us quite awhile since we were reading the rules and stuff as we went.  so we didn’t use all the weapons and such as efficiently as can be done, of course.

i will look up those 3rd party rules, as like was mentioned, there seems to be some funkiness to the box rules.