in the spreadsheet linked here to calculate mot_thst_expo, the formula for corrected thrust is:
=F12*$G$8+$G$7
but it should be
=F12*($G$8-$G$7)+$G$7
youre welcome
hmm this is in the core ardu docs yet still not corrected. i suppose if it was too easy to tune, there would be less customers for consulting businesses.