Responding to my own recent post. I have the Mac TurboTax desktop version. After talking directly to a TurboTax representative I got clarification. (Not to say the software isn't very confusing and misleading.)
If one pays the State eFiling fee by credit card, there is no Maximum Refund Guarantee fee. I went through the process with the Rep on the phone (to make sure). I only paid $15 for State filing. ($10 Costco credit applied to the normal $25 fee). I filed my taxes successfully.
However, I was told if you have TurboTax take the State filing fee out of the Federal refund, they do charge $15. I obviously could not verify that.
