You thought wrong...

Sensored means that the speedo can be told where the rotor is, but it cannot be told how the fluctuating interaction of the magnetic fields is. When the speedo knows where the rotor is, it can tell you angle and speed.

Knowing angle means the speedo can work out when to fire the coils in relation to the instructions you gave it in the programming box. If you told it to increase the timing by one degree per 200 rpm (boost), the speedo will do just that. As it knows what the rpm is, it will deliver one degree every 200 rpm, and if it doesn't see the rpm, it doesn't deliver the timing.

However, when you tell it to put in turbo after X seconds at a rate of XX degrees per seconds, this has no relation to revs - it just does it. So, if the motor has achieved 70% of the boost revs when the turbo comes in, that can be too much timing, causing a poor interaction of the magnetic fields, and thus the motor stops accelerating and just generates heat. That is why turbo is so useless on short tracks, because it comes in when you tell it to, and not when the motor can accept it.

ALWAYS use gear ratio, boost and boost 'timing' (200, 250, 300, etc.) to tune the car on the infield. ONLY if the car is at full speed 2/3 the way down the straight is it useful to use turbo. It's like it was in the old BR days - spring type and pressure, brush type, magnet strength and gear ratio all had to be right for the car to be fast.

If you only use boost, then you are right, once you have found the right settings to get the car to accelerate fast, it will always do that. The problem comes when you throw in turbo, as that is not related to motor speed and that's when the heat problems start. HTH