I've used the M1s for years and not noticed any issues with the ADBV or the flow rates that some are uneasy with. The UOAs I've posted on several vehicles, usually with M1 filters, show outstanding performance. The M1 ADBV is made of the the higher quality silicone material, versus the nitrile rubber, so who knows, but I doubt it's a problem with the ADBV generally. That said, perhaps you got a bad one. Switch around while keeping the same oil to minimize the number of factors changed at the same time. If another design works better on your car, then obviously go with it.