So, if I understand you correctly, you are using pushrods drilled for oiling, but the lifters are not sending oil thru the pushrods? If so, I am not surprised that you are wearing the cup end of the adjusters, as your cups have holes to allow the oil the rockers are spraying into the cup, to drain down to the lifter, rather than "fill up" the cup, to keep the adjuster ball swimming in oil. If this is indeed the case, I would switch to pushrods without holes. I ran the erson roller rockers for many years, with regular ball and cup pushrods (no holes), and never had any such issues.