If you're a good tuner and don't race, 10-12% oil is fine really. I run 8% castor 30% nitro in my car engines though my usual brew is 20/10. I attribute the OPs usage of the break-in from the mfg. started the wearing out process. Idling for long lengths of time is the wrong way to break-in and right way for wrecking a car ABC engine. The conrod ends and the piston do not mate together with their respective parts properly unless ran at a rich high rpm setting. ABC & AAC liners need that hot and fast running cycle, especially if it's a tight engine which is critical to conrod life. Performance engines have a little more clearance between the conrod bushing and the crankpin and/or between the conrod and wristpin. High rpm keeps the conrod bushings pressed against the one side of the bushings allowing a bigger pocket of oil behind the crankpin and/or wristpin.