Paying for the flying that you dont do !
Another major factor is the weather , last month my aircraft did about 10% of the work that was booked !.
The fixed costs are the same if I fly one hour a month or one hundred with Florida Weather and USA fuel prices I could get quite close to the price per hour in the USA despite the extra cost of parts and the JAA .
As for the owner not helping with the maintenance , under JAA there is nothing to stop this happening except the attitude of the owners , most would not be seen dead working in the hangar after all if they did some of the maintenance it would give them one less thing to whinge about !.