The last time I was involved in checking ISO speeds, we found that indeed many manufacturers played fast and loose with ISO and speeds of some products were as much as one stop out from the ISO standard. This was a particuar problem in color where one layer might be off and the other two on. Or, you might find it varying from batch to batch.

So, Kodak has always been very careful about making sure that all products, color and B&W, are up to ISO standards in all respects.