I have a 2007 24SSV, my understanding is that when you activate Supra's version of TAPS it does cycle down automatically. It will remain down (or up, can't remember) to get the boat up on plain faster, then when you are approaching the set speed it moves to the rider's preferred setting. I have not had any problems with it not functioning as of yet.
I understand the frustration of having to tow 2 hours one way for service. I just had to pull mine to Houston, about a 2 hour pull, just because the check engine light came on due to a battery not being fully charged!
2007 Supra 24 SSV 340 CAT
Lake Bryan, TX