Since the power displayed in this scenario is a calculation from your speed and the resistance requested of the turbo, and it is lower than your power meter is reading, that would suggest that the resistance applied is actually higher than the simulator required, i.e. the simulator is assuming a lower resistance and calculating a lower power than the trainer is applying and the power meter is actually observing.
30-32 Kg is very very low weight and it is not that surprising that the trainer/simulator are not well calibrated at this level.
At a much higher weight, the power calculation is higher than actually measured, suggesting that the trainer is failing to apply the resistance level requested of it by the simulator. This makes sense, as at higher weights and therefore higher resistance levels, it is likely that the trainer is struggling to generate enough magnetic braking.
So although it is only the speed that matters, the power displayed does suggest that you are suffering higher resistance than the simulation should require, and are therefore working harder to get that speed than you should have to.
The Handicap will have taken this into account as it is set from the bkool calculated power, which if it reads low will result in a lower weight handicap!
EDIT: Perhaps in reality it is not practical to have a handicap weight as low as 30-32 Kg, and you are gaining little benefit from this. Perhaps we should set you at something like 50 Kg? One way to try this is to do the runs at a range of weights and see at which point your times start to lengthen measurably?
Geoff