Most of those promos for X number of round trips have to be purchased in the more expensive classes. The el cheapo's generally do not qualify. The restriction also usually requires you to be on NW metal not on CO or DL metal so even if you could roll other programs miles/segments into WP (which you can not) if they were not on NW Jets than they would not help you anyway.

The reason for doing it this year would be to enjoy the benefits as you requalify next year. If you don't mind loosing the benefits for a couple of months (50% bonus miles, pre-boarding, and a possible U/G) than I would fly on specials through Jan and Feb to get to 25K miles and then be silver until '08. If those things were important I would take the one extra R/T that you do not have booked on NW metal before the 15th of December.