TMax 400 has better resolution (or detail) than FP4+. It has one of the longest straight line curves of any film, will react very well to agitation changes you make to shape that curve into a shoulder if you like that better. When you take this film to the darkroom and print it, or if you use it with a scanner that can actually resolve grain (like an Imacon Flextight), you will know what the full potential of TMax 400 is. Until then you're just seeing an approximation.
I attached three images that are scans of prints. If you can tell me whether they are TMax 400 or not I'll be very impressed.