No, what you're saying is irrelevant. I don't know whether this chart's data pulled from salaried, hourly, or both, but the basis is still the same. I'm not going to do your homework for you, because you're not worth it, but there are plenty of studies that show the salary converted to an hourly equivalent and the results are identical. So you're just blowing smoke, as usual.
Yes, any study I've seen which shows this same result merely *normalizes* total income by hour. I'm pretty sure this graph is simply taking data from the Current Population Survey (CPS), which doesn't just sample from people who are earning an hourly wage, it samples from wage/salary earners and asks how many hours they work a week and how much they earn total and then normalize by hour.
So Loren's claim, is as usual, merely a reflection of his persistent ability to deny any empirical facts that contradict the neat and tidy models he has decided are unadulterated truth.