A leakdown may be a better test in this case. I've seen the wrong oil rings packaged, as in original size in a "30 over" packaged set. 2nd ring (s) installed wrong. Using syn oil and going to "easy" on the initial break in and glazing over the cylinders, bad hone prep, untrue bore finish, loose guide clearances, bad valve stem seals, Ring design and materials not matching bore finish. You may just have to put on more miles to see.