Unless you flow'm yourself, you have to 'trust' what you were told. BTW, I have never been overly concerned about flow matching, albeit, one owuld prefer a matched set.
As for running 11s, and using the 60s, I, personally, would not worry.Just chip itcorrectly and check your plugs after some normal drive time, just to confirm you don't have an overly lean/fat cylinder. ifyou do, only then would I begin to think they were not flow matched (assuming everything else is in proper working order)
BTW, just did the 60s and an extender extreme and would say ful throttle has the chip 'dead on' right out of the wrapper.
Good luck and enjoy!