Not a T-MAX issue at all Mr NG.
This is all on-board computer programming
In Tech section, you need to adjust MAX TIME BODY MINUTES
sounds like you did that
In Salon Operator Section, you need to adjust MAX TIME BODY MINUTES
AND
SESSION TIME
"Session Time" sounds like it has not been adjusted back up yet.
P.S.
If you need the Owners Manual on PDF file, rather than the hard-printed from mfr, PM me an e-mail addy and I'll send it off to ya.
sparks