When I left a couple of years ago, I was told by the CAA that I could add a percentage as per the agreement mentioned above, but only up to a maximum of 75 hours, to my RAF total. This is unlikely to affect those needing the 1500 hours for an ATPL, but will almost certainly affect those looking for 4000 or 6000 hours to make them eligble for a command. Whatever you do though, get it in writing from the CAA.
Hope this helps.
