It's the 3:26s and 3:27s, as well as running for a doping coach with doping partners in a country rife with doping positives, that makes him suspicious, not the consistency below 3:30, in the sense that it isn't that hard to run lots of times within 4 seconds of your pr--it's that your pr is absolutely incredible, so that you can be well off your best and still breaking 3:30.
As for the 10x400 at 53-54 with 30 seconds rest, which is what I read, I think it is plausible and it is the reason that he said publicly that he thought he could run 3:24. Think about it. 10x400 is supposed to be close to your mile pace, although on more than 30s rest, and he was able to average 54.8/400 for a 1500, that is, 3 3/4 laps with no rest. He should have been able to break 7:20 for the 3k, given that workout in any case, and likely he would have if he had had better pacing in his attempts.