Hard shifting after tune installed

I just had a tune put in my Silverado 2500hd 6.0, now it has a hard shift when it kicks down from higher to lower gears, I can feel it in the floor. Shifts fine when accelerating hard. Not a firm shift just a clunk when it changes gears under moderate acceleration.it does not seem right .Feels like it is bad for my transmission, I do not like it at all. it was smooth as silk before custom tune. Also feels like I gained some power at high rpm's, but lost power at low rpm's . Is this just a bad tune up? Is this bad for my transmission ? They advanced my stock timing from seven degrees to seventeen degrees and added more fuel, they did not say anything about adjusting TCM? Any idea what may be going on ? Any advice would be greatly appreciated, I am going to take it back in tomorrow.