Another Rotorcraft Question...

... I've been noodling around doing searches to find out how much it costs to keep the Kiowa Warrior (OH-58D) and other Army rotorcraft flying -- cost per flight hour -- and I'm finding wildly variable numbers ranging from around $960 up to around $10k per flight hour.

Ideally I'd like to know how much is maintenance parts/spares and how much is the time and effort expended keeping it running, though total cost (including maintenance hours, fuel, etc.) is fine as long as I know that's what it is, and have a SOURCE for this info ("Some Guy's Webpage" isn't a very good source)