For the record, my Garmin posted the following times today for the tempo run. It measured that we ran 2.89 miles total so the last entry below if shorter than a mile.
mile 1 – 9:49
mile 2 – 9.44
mile 3 – 9.22
So all three miles were faster than my mile time from the 2 mile time trial (19:57). Hmmm, what should I read into that? Should I have backed off? Note that my warm up miles were on average 12:30 which is 30 sec slower that my current MGP which seems about right for me – so warm up was OK.