What determines what speed an escort chases you at ? I'm guessing the .exe file.

I.e., doing some experimenting and many times when they should be using their top ("fast" on the chart) speed during a surface chase, they're stuck in medium instead.
To easy to outrun them then. I'm aware u-boats could do so irl early war but I wager the escorts were going full speed too.
Still can't get them to fire their guns when they should either. I.e., I'm within 1500 meters, they're chasing me so they see me, .........nothing and eventually I pull away and leave them behind.
They should be blasting away in such circumstances.
This is in various installs with nothing overwriting the escorts files.