star,
Since your WCR is 2nd hand, who knows what was done to it or how much oil it has soaked. Since with the same drill, the WCR should NOT be 8 boards weaker than the BRB, may I suggest 2 possibilities:
1. Resurface the WCR to bring it back to specs. Then see how it reacts.
2. If #1 does not restore it to being close to the BRB (it should be slightly earlier, with less backend and slightly more overall hook, IN GENERAL, for the average rev and avg ball speed bowler), then maybe it needs an oil rejuvenation procedure.
(Keep in mind that house blended oil patterns can mask the difference between many balls.)
Abralon has worked for me on all the Lm/L balls EXCEPT the diamond particles and the Masterpiece. I needed to use Trizact pads to affect these balls surfaces in a true way. Sandpaper and Abralon will have a slight affect on them, but their surfaces or particles are too strong for anythign but Trizact or Haus Diamond pads. This is my experience; it may not be yours. (YMMV - your mileage may vary.)
--------------------
"None are so blind as those who will not see."