Did the dealer reflash my ECU and lost Mail in reflash mod?

Hey guys....
I just got my truck back from the dealer. I guess all 04 Titans have gone through the problem with the master cylinder and brake booster. The dealer just replace both. $800.00 down the drain. After picking the truck up, I kinda noticed that it wasn't running to full potential. It didn't have the "get up and go" feel like it use to have. I noticed that the mileage on my speedo had reset and figured the dealer must have reflashed the computer after installing the brake booster and master cylinder. I still have the function of the three maps...stock, performance, and security, but just don't feel the power it used to have. If the computer was reflashed...do think the Titan is relearning the Uprev mod again? If it is...then I 'll drive it for about 100 miles and wait to see the difference.

I just received my copy of Osiris in the mail. If the reflash totally erased the Uprev mail in reflash mod....will the ECU accept the new mod I received with Osiris?

Any input would be greatly appreciated.:crying: