Spence,
That's what we need, easy to understand rules.
I want to add the following FORMULA that should be used to determine the maximum allowable bet for pot-limit. Any player facing a bet, may raise 3 times the largest bet required for a call, plus the remaining trail, plus the pot. Example: Pot size 100, Player A bets 50, Player B goes all-in for 20, Player C wants to raise “pot.”
Answer: Three times 50+20+100=270.
Formula works for any player when it is their turn to act, even the under the gun position pre-flop. Example: Blinds $5 and $10. UTG bets “pot.” Three times the Big Blind plus the Small Blind. Three times $10+$5=$35. PLEASE NOTE: The small blind is sometimes counted as a completed bet to the Big Blind, this will allow the “pot bet” to increase to $40.
I used "the largest bet required to call" instead of your "active bet" but either one works for me. I think it breaks it down to it's simplest form