A few weeks ago, I was running just Torrie's basic 93 tune in my Flex. The DA was around 2700 - 75-80 deg, and I ran exactly the same 1/8 mi time as your best (also my best that night). My 60' was a bit better, like a 1.95. Unfortunately, there was a big 1/8 mi meet the following day so they were not posting 1/4 mi times. Calculating from tables put my 1/4 around 13.4, which is the best I have done with just a canned tune.
I do have PPE Downpipes, a custom exhaust and CAI, plus smaller diameter tires. But.. Flex weighs at least 450lbs more.
When I run w/m, my times are .4 to .6 better depending on DA & temp, so you should have been running in the 12's. Log your tune with W/M on in first and second, and send it off to Torrie. I'm sure he can tweak it to run somewhat better. He has been in Houston tuning cars, so may not get back as quickly as usual.