I'm glad you got good results. Testing is always the best way.

The following is from Kodak's tech info bulletin for P3200, and I had it posted at the front desk of the lab I used to work in. I feel that the P3200 designation is at best misleading for most developers, so I always throw this out when people start asking about EI ratings for P3200. So for what it's worth:

KODAK PROFESSIONAL T-MAX P3200 Film is specially designed to be used as a multi-speed film. The speed you use depends on your application; make tests to determine the appropriate speed.

The nominal speed is EI 1000 when the film is processed in KODAK PROFESSIONAL T-MAX Developer or KODAK PROFESSIONAL T-MAX RS Developer and Replenisher, or EI 800 when it is processed in other Kodak black-and-white developers. It was determined in a manner published in ISO standards. For ease in calculating exposure and for consistency with the commonly used scale of film-speed numbers, the nominal speed has been rounded to EI 800.
Lee