need advice on wood splitting

So there's this old timer in town who like me, has his hand in a little bit of everything. Trash hauling, scrap metal, fire wood etc.... I've been BSing with him for well over a year when I see him at the dump etc. Well he flagged me down yesterday as I drove past his property. Says he's getting too old for this s#!t and asked me if I wanted to cut and split 400 (yes 400) cords of wood for him in the spring. I said of course! Here's the problem....... I know that spliting a cord of wood that's in rounds alrighty is 25 bucks a cord. (The young buck that works for me and I can knock 10 cords out a day on a bad day) 15 on a good day) BUT what I don't know is what to charge him for cutting the logs up into rounds? Some of these logs are 3-4 feet across...... I have everything I need to do the job except a HUGE chain saw which I'm working on getting now.
So, how much do I charge him for cutting the logs into rounds??



P.S. I have a feeling this will be an every year thing til he dies........