YEah, the iPhone app works pretty good...they are very close to actual times.
No offense, but your 60' times SUCK for being a 6.2L AWD. I am a 5.3L 2WD ECSB and my best 60' time is a 2.1. Sure, Nelsons mail order tune works great, but that specific truck needs a live ECM and TCM tune for it all to sync correctly. That motor is being cut back SO much by the ECM/TCM.

Do yourself a favor and buy HPT. That way you can send and receive files to tune your truck better.