I tried the times backwards and trackbot had the same answer (of course, in reality, it would be far, far more difficult to run 38/70/66/55 than to do the 38 at the end), so I think it is time that we recognize that there is a very good reason that Asbel Kiprop and the other sub 3:30 guys could at best get alongside Centro in the last lap and could not hang with him as he was upping the pace that last lap: it was an extremely good run, worth sub 3:30, and surely this will be the year that he throws down a 3:28 or 3:29, because Centro is that good. I say he'll run faster than this optimization because there were multiple 3:26 (Kiprop), 3:28 (Makhloufi, Iguider) and 3:29 (Willis, Souleiman) guys near him in the last lap and they could not stick.
Opimized time for 3:49.0 1500.0m based on even pacing:
I am a bot. Info: habs.sdf.org/trackbot
Wrong. Trackbot is using that calculator incorrectly.
The actual optimization for the times you posted is:
You entered - 3:49.0
Optimized Time - 3:37.90