Based on either the Max EGTs you set or the Max Boost you set, the TST R49 will begin defueling when the Max is reached for either one. Not a complete loss of power, just defuels until under Max setting. Although on the track it does seem like a complete loss of power when I forget to disable the features.
The TST twins program is a program designed to fuel heavier and more I think at lower boost levels. Designed for high horsepower engines with twin turbos or large single turbo replacements.