Surely if you have 30 aircraft all getting maintained it really shouldn't matter whether you take the financial hit on he maintenance as it comes or against future use. The effect should average out to approx. the same.
With regard to Ryaniar's costings in an earlier thread I suggested that he would sell the a/c to a leasing company and pocket the difference. In a subsequent newspaper report MOL did suggest that their depreciation policy was on the purchase price on a reasonable timescale.