In the UK I gather that when TV broadcast royalties are collected, that 50% goes to PRS and 50% goes to MCPS.
So if your contract says the library collects all the Mechanical royalties, then overall you only get 25% of the TV royalties. So if a US company sets up a sub publisher in the UK with both PRS and MCPS membership, they then get the mechanicals, even for US composers (so 75% of the overall pot to the publisher).
Is it common for libraries to collect 100% of the mechanicals, even when they’re non-exclusive (or exclusive without owning the copyright)?