We suffer greatly with the RPL vs Actual CFP FL.
The RPL levels are generated using zero wind component ( 'still air' ) and full weight. These are stored in the CFMU database.
When the actual CFPs are produced, and the real live weather added, plus actual weights, the difference in filed level ( RPL ) and level requested by crew ( performance level ) can be dramatic.
Of more relevance to the topic, the crews on an RPL flight would have no idea of the RPL level - only what their CFP ( computer flight plan ) says !
And just to add more confusion for ATC and themselves ... we often have to live file several sectors for various operational reasons ( ie swaps between different fleets etc ) so one day a flight would be on an RPL ( and 'iffy' filed FL ) and others an accurate live file !
The answer logically would be live file them all. But with 300 odd flights a day ?!