I would say both of your 400 times are very good considering your 200 PRs and perhaps, as tr400 has stated, speed development is a thread of training that should be more emphasized.
If I recall correctly, KitKat’s 44.3 guy ran 10.5 and 20.x PRs. It is also my understanding that KitKat also takes more stock in rolling 200s as opposed to 200s from the blocks. His 44.3 guy could run in the 19.x for a rolling 200, I believe.