Wrt the suggestion that they asked to climb in order to avoid 'clouds'.
Imho, it's a very foolish thing to try and out-climb a thunderstorm.
Even if there is no cloud above a Cb, that should not be taken to infer that the air above the Cb is free from severe turbulence, and all that climbing would do is put one even closer into
coffin-corner, at a time when (
if sever turbulence occurs) one needs as much airspeed margin as possible.