How well will AW 18650 hold it's current for a P7?

I have a P7+7135chip+salvaged samsung/lg ICR18650's and they can only do about 2A-2.4A on high fresh off the charger but fairly quickly drop BELOW 2A on high. I don't know if its because the limitations of the linear buck 7135 or that the 18650's are ICR or perhaps older with some resistance built up but do you guys think or know that AW's will sustain that 3.7v ~2.8A current until it depletes? The ones I am using taper off current greatly as they deplete. Or, would I look at IMR's for a P7? I just want to run a single cell btw.