The ~$2000 you would spend for 20k PQM to get to Platinum a couple of months early would be much better spent towards upgrading your existing fares to a premium class (which is more certain than the merely better chances of a CPU or upgrade on those flights). You could also use it to purchase RDM if that's what you want (as compared to higher multiplier) or drinks, that platinum will get you 5 of free (using coupons) on domestic flights.