I have done many film speed tests for myself and customers over the years. Generally speaking most films test to within a stop of their claimed rating. TMY however is a different kettle of fish. I have never been able to get a zone 1 density anywhere near 400, the best was 125. Either this film has a really weird toe or I don't know what. OTOH, I have seen supurb work done with this film but even then it has what I call the "dreaded TMax look"(posted 8909 days ago)Personally I love TX and VP but I think TMX and TMY are the pits. your mileage will vary.
Mark