Every time I've done my development calibrations the effective speed that I determine is lower than the film's rated speed. This has been true for three different developers although the change in speed was not the same for all three developing agents.(posted 8714 days ago)ISO speeds (ASA is gone now) are determined by a very specific set of exposure and development steps using a developer that is not commercially available. The whole system is there simply to provide a common ruler to allow different films to be compared. You will have to determine your effective speed by your own measurements.
But, not to dodge the question: I use PMK developer and rate HP5+ (ISO 400) at 250 and Delta 100 (ISO 100) at 64. These speeds produce a Zone I density of around 0.10.