With enemy ships around it's better to go at lower TCs as the game makes the AI smarter with higher TC.. It seems to skip a few calculations or it's just the simple calcs used that makes it so.
For example..silent running in a rough see the AI usually cannot see your scope beyond 1Nm... add some TC and you have a destroyer on top of you in no time.
Sometime ago with the SH(3) engine, it was discovered that a TC<=256 is the sensible limit of the game. It starts 'losing track' of things beyond this.
