as pointed out by kb61751, the 13# P32 wolf spring in the P3AT does not go solid at full recoil.
The 13# rating is with the spring solid, so in a P3AT, the full recoil force will be less.
Even though the spring constaint is greater (force/deflection), with the spring's free lenght significantly shorter, the force at slide battery is less.
making adjustments to the springs free space with washers could allow the full 13#s at full recoil, but would add very little to force at battery
Not Knowing Wolf's finally tempering process, but assuming "the best process I've read about" the pitch to strain appears to be above yeild so the spring will "wear out" with a few hundred cycles. I think by thier P32 springs being over maximun material properties explains why they can not make a spring for the P3AT.