Tell them the other Allison dealers quoted you $29 per gallon and see what happens. You can always have it shipped and still save money. I just bought 3 gallons at the Allison dealer next to the Oakland Airport and it was $29 per gallon. Filters are $8.53.
I changed the filter at about 6,500 and then switched to the deep pan and TranSynd at about 15K. I just flushed the fluid and changed the filter again and replaced the TranSynd at 25K. Used TranSynd again as great stuff and highly recommended by Allison and GM. I do a bit of towing in the summer and wanted the lower Tranny temps with more and better fluid. I believe I am at about 99.999% pure TranSynd now and based on extended drain from Allison I probably won't change it again for 100+K. I'am done with that for next 5 years LOL. Nothing else on the market will let you go that long.......period!
Take the time and trouble to get the TranSynd, it's well worth it. If you are going to be towing consider the deep pan and long pickup screen as well. Cheap investment!
Good Luck
\'01 Chevy EC/2WD/SB, T/F 45 gal, Delvac 1, TranSynd, deep pan, MAG drain plug. Escalade handles & painted bumper capto. After market grill, billet bowtie, Stockland cover, no side trim, no juice, no gauges, nuttin but stock! Nicktane Big CAT Pre-OEM. Gone, but not forgotten.
'07 Crew Cab LBZ stock all the way except added 45 gallon Transfer Flow tank and billet grille. Great truck also now gone, but not forgotten.
'12 Crew Cab stock for a few more days LOL