TDC malfunction or am I doing something wrong?

[hunter301]

While I still use God's eye View (F11) when playing and event view I started doing full manual targeting for the realistic feal of the game. I use the (F11) and event view just for the cinematic fun of the game. Maybe later I'll run a couple of full realism games just to see how badly I can screw up...lol.

Anyway I ran a couple of the training courses with full assist on so I could see exactly what the TDC and Attack Data Tool were doing and to confirm what I thought they might be doing before switching over to full manual targeting.
I like to set up my already loaded torpedos ahead of time so I won't waste time in battle. Speed, Depth, Spread, etc....
However there have been a few times where I'm trying to set up my forward and stern torpedos to high speed because I'm battling destroyers it won't let me switch over from low speed to high speed.
Does anyone know why the game won't let me switch from low to high speed on a torpedo that's already loaded into the tube and ready to go?