Has anyone experienced this; somedays my 20mg oxycodone SR which is supposed to be the same as oxycontin and last me 12 hours seems to almost last that long. Other days the same pill from the same bottle will only last six hours. I have a painful peripheral neuropathy, and sometimes the pain levels are not consistent, they do spike if I am stressed or tired, but not enough so that a 12 hour time release narcotic wears off in 6 hours. It makes me wonder about the quality of the medication and the manufacturing process. Of course, it could just be me.:confused: