[Weightshift]

The ball gets 70% of clubhead impact velo, which is 70 mph if the impact velo is 100 mph. In addition it gets 100% of clubhead separation velo, which is at best 80% of impact velo due to energy losses. So assuming the best case, this gives a separation velo of 80 mph. So ball speed is 70 + 80 = 150 mph.

Thanks indeed, now I understand.