Okay, here's a better system with easier math that I'm sure works:
Each bot gets a new variable which is it's angular velocity. It holds over between cycles, however, the .aimdx, .aimsx commands still work relative to no turning.
So a bot that wants to spin at a constant speed would do 5 .aimdx store every turn still.
Each bot is charged:
.002 * mass * radius * abs(new desired angular velocity - old angular velocity)
and new angle = old angle + new desired angular velocity) (That's a Euler approximation for you numerical analysis types).
nrg for the turn. I can show the work process I used to get this if you like, or not. Rest assured, it's an accurate mathematical model.
Now, say you aren't moving at all. Then you do 5 .aimdx store, then do nothing. What are you charged and when?
Well, the first turn you're charged .002 * mass * radius * (5-0) = .6 nrg for a normal bot.
Second turn, you're charged .002 * mass * radius * abs0-5) = .6 nrg for a normal bot.
So constantly spinning becomes a very good strategy still for when there's nothing to eat, since you're only charged for starting the spin and ending it. But turning constantly and drastically in combat uses alot of nrg. Trying to turn 90 degrees would cost nearly 38 nrg, and then another 38 nrg if you stop turning the turn after.
I think I'll also add a new component to a shot's vector that comes from the bot turning. If you're spinning really fast, the bullet is going to veer off from what you'd expect it to do if you weren't spinning. Like a sling.