Since Larry won't answer the question about the label, let me take a shot at guessing.
Obviously, the 8 oz. per gallon suggestion on the label, for pump up sprayers, is too high; however, most carpet cleaners are so used to 8 oz's per gallon mix ratios, that they automatically opt. for that. If it is on the label, they will go with the flow, unless they are directed otherwise. Larry sells more product, and most BDCC's are none the wiser.
I think Larry is happy that way.
I have been using it for two days now. It is too soon, of course to make a fair comparison yet, but for the past two days it seems that mixing PM at 1.5 oz per gallon is not quite sufficient to compare well with Judson's mixed at 2 oz's + 1 scoop of booster (which is my normal prespray). I do a school tomorrow and will try PM at 2 oz. per gallon.