For what it's worth in the early '90s (I know, ancient history maybe) the UK CAA accepted OPCs (then Base Checks) by certain examiners as being acceptable for several London-based Helicopter charter companies as far as freelancers were concerned. This saved the stupidity and inflexibility of doing two or three identical checks just so they could be assigned to different AOCs - clearly a daft practice.
There is a precedent of sorts.