In the crossover years of the Trek takeover, the company used its existing inventory of tubes to make frames. Trek kept the same positioning of the models Pulse—>Attitude—>Adroit but it didn’t have anymore of the boron/carbon fiber reinforced tubes to use for Adroits. So, tubes originally meant for the Attitude were repurposed for the Adroit (these Adroits would now have T in their serial numbers instead of X’s, with some exceptions); tubes originally meant for the Pulse were repurposed for the Attitude and that’s why these Attitudes have P’s in their serial number. Hope this helps.