Allison 5 speed tuning

Anybody know why in the stock tune for the part throttle downshifts, the 0 % TPS downshift speed is 2 mph higher than the 6.3 % ?
I have a 2002 Allison which has a known problem called a flare and bump, when you slow down for a stop but don't stop completely and get back on the gas it flares and bangs down into 1st. Never had it fixed for free, I know there is a GM tune out there but cant find it. Anyway I figure the problem is the 2->1 shift speeds are set too low at 6 mph its not making down into 1st on a slow roll, so I want to try and set it at 12,14,16,18 mph just wondering why the stock tune in the 3->2 4->3 5->4 downshifts at 0 % TPS is set 2 mph higher so I can rule that out as a possible
cause or cure for the 2->1 problem ?

Any help is appreciated. thanks.