I'll repeat this more clearly.

When I was at Kodak, the last time I checked, the release test for B&W films for speed and contrast was D-76 at 68 degrees F. If the PX did not meet the ISO 125 speed and the proper contrast, it was scrap. The times have been published in the same Dataguide I mentioned above, and curves and other info are on the Kodak web site.