The routes are all stored in the box in both aircraft types but without a paper flight plan you don't know which route (of the several sometimes) you are supposed to fly. Hence the possibility of a delay if you cannot get the paperwork.
EZY switched to LIDO from Jepps flightplans a month or so back. The new flightplans were tested at a couple of bases before the whole network went over. The switch itself was fine and went over without any real problems. Few grumbles about the new flightplans though...........!