Yup, it's not that big a deal in terms of the difference in numbers. It just makes very little sense for a tuner in the USA to use a DIN correction factor, so it makes curious folks like me wonder if they are just that sloppy when printing out the charts for the customer, or they think that extra 1-2% will make a customer think they are better tuners than the guys down the street.
The numbers from a DynoJet aren't exactly ultra accurate anyway, but that doesn't mean they shouldn't still be corrected consistently with the same widely accepted standard used by the rest of the industry in this country. That would be SAE. Not uncorrected, not STD, not DIN, but SAE. It doesn't take any more effort for a tuner to use the SAE standard, so why do some still resist? It's because SAE will give lower numbers, and even 1 or 2% might affect advertising and bragging rights I suppose. Much easier to mislead than to educate customers.
Jerry