I was looking at the nutrition book today and my goal with the program and the nutrition is to lose fat the first time around.

I am pretty big now about 5ft 8in and 255lbs.
So based on this my energy amount is 3660. And they want me to use level III.

Is this right? I am sure that I dont eat anywhere near this now, I'm thinking I eat around 2100 to 2300 maybe.

I was hoping to eat 2000 to 1800 to lose some weight.

Any ideas?

I would go by the book. I'm level 1, didn't have too much to lose, but needed to tone. When I started, the first few days, I could barely get all the food down. Now that my body has adjusted to the food & workouts, I have days where I need more than they suggest. I think once you start, you'll realize you need the food for fuel to power thru the workouts.

If your main goal is to shed pounds quickly you might want to try Slim in 6 first and then P90X after to work on your body composition.

Also have you read page 1 of the Nutrition Plan? It explains in detail why you should eat at least 3,000 calories.