increased voltage

changed from MPG tune to 87 perf tune, and noticed fans come on sooner, and
volt meter reads over 14 V all the time,
thought I smelled batt hot, (sulfur smell)
is this normal?
on 2007 silverado, 5.3, new body- v9r28

well, I removed the tune and the voltage went back to normal, fans don't come on until its warmer,
so I tried it again, I installed the 87 perf tune, and immediately the voltage went to over 14 volts.
so...
something in the tune is causing voltage spike!
i returned it back to stock, as I do not need to be frying batteries,
I'd say this unit is TRASH!.
i won't sell it to anyone , as I don't want others to fry their batteries,
I guess it'll be target practice for my .22.
surprised others didn't or haven't had this problem.
thanks for the help.