I don' t believe captive pivoting limb pockets give peak efficiency, but they do provide for better " tightness of tolerances" vs. having loosened limb bolts in fixed pockets.

I' d be curious to grab some of our high-speed video equipment from here at work and film a fixed limb pocket, 60-70# bow that has been back off to the minimum of 60#' s and see if the limbs ends in the pockets ever " bounce" away from the limb bolt heads during the shot process......

I' ve always been a fan of the pivoting pockets myself.

Yeh, I don' t know what is going on. I hit " ok" and I end up with 3 posts, half the time. [:' (]

I' ve found also that if you have a 70 pound bow maxed out and the draw length is perfect for you, when you turn the bow down to 60 you will see about 1/4 inch of draw length increase. This is with standard fulcrum type limb pivots, the pivoting limb pockets may be different depending on the thickness of the pocket