It is hard to compare various hand times. I know mine are very generous compared to others but I build that in to my idea of conversion and it works well for me indoors (where there is no wind to screw with results one way or the other. I then would build in a margin for outdoors. IE in 1987, I times Ben from stands in times I figured would give him 9.80 and predicted 9.85 to allow a bit of wiggle room. and in 88 I figured 9.75 or so and predicted 9.80. in each case he was in the middle somewhere.
When you have a substantial training background over years, you can look back and see exactly at what point you performed at your best and then try to match that point the next time to be at your best again. That’s what planning is about. Read my next general post for more.