No that is not the case.  I believe it is now 400HWL withdrawal limit on both Mac and Windows.  It probably is the case on Lux as well but dev can answer that.   It was the case that you could withdraw after mining 20HWL.  I suppose dev decided that the 20 limit could be too low, the tendency of people is to want to withdraw as soon as they hit the threshold.  It was certainly the case for me, i withdrew mostly after mining 20HWL except for what i mine overnight.  Depending on the number of people withdrawing at the 20HWL limit, tx fees could become an issue if each withdrawal is handled as a separate transaction.  I suppose it would be better to combine for addresses though. 
We'll know more once distribution is done by dev on Monday.