The relationship between where lifter and cam sit together is designed into the position of the liter bores in the block and the position of lobes on blank. If the lifter has the correct crown and the cam has correct taper no amount of machining of lobes will alter the contact point. Most mass produced cams are tapered one way only as are redressed cams on large production runs to save time on setup costs, tapers usually run in conjuntion with direction of thrust of timing gears. The problem of wiping lobes only came with the replacement of forged steel cams with nodular iron cams and poor oiling systems. I have seen lifters from forged cams totally stuffed from years of mileage without damage to lobes,we are stuck with design problems and theres no way out.