Was aware of the FL rule but neither Chelsea, Everton or Man City are in the PL. also I haven't read that the wages are then charged to the club where the player goes on loan in the PL.
It would be to clubs like Chelsea & Man City to keep their wage spend high so its quite probable that in the case of say Lukaka the fee would have included minimal sums in relation to wages and the bulk of the fee may well have been scheduled as the sum that Chelsea will have amortised in respect of his transfer fee during the season. We just don't know how the few is made up & that's why it would be reckless to just dismiss any FFP issues