Hi Roland,
Good to see the critter is doing well!
Its a fallacy that scorpions will gorge themselves until the burst or die. This being said, its never recommended to overfeed the scorpion. I do find that young can be fed a lot, and may be allowed to get slightly plump/fat, but this should not be maintained, and there should also be a period for the scorpion to digest its meal.
Don't be stressed if the scorpion is not as active as usual, its normal for the colder months, and they will also not eat that much, or may refuse food completely. Just ensure there is a small wet spot by the water dish to help aid in shedding should it become time for that to happen. You will only notice significant growth once the scorpion has had another molt. Parabuthus matures as follows: Males at 6th instar and females at 7th instar. You can expect anything from 2-4 molts per year from your scorpion, but this is VERY dependent on the conditions you keep it under (temperature, feeding etc).
Regards,
Jason