Hi, this is the reply of Rolls Royce about this topic.
"Dear Sir:
When shutting down the engine, Rolls-Royce does not recommend motoring the
engine directly after shutdown unless an after fire has occurred. This
practice introduces relatively cooler air onto the heat soaked first and
second stage turbine wheels and can accelerate rim cracks. Please reference
Rolls-Royce CSL 1178.
In regards to starting with high residual temperatures. We recommend the
engine be motored to get the residual TOT down to 150 degrees C or as close
to that as possible with out overworking the battery. It depends on how
long after the engine was shut down and ambient conditions, that it will
take to motor the TOT down. We do realize that there will be cases where
the engine will be started back up shortly after shut down, however, any
time elapsed between shut down and start up is considerably more desirable
than motoring the engine immediately after shutdown as discussed above.
Also, when attempting a start shortly after shutdown the operator needs to
pay caution that the battery energy is not effected to the point that a hot
start may be encountered at the upper ranges of the start sequence. "