Embedded taxes do not represent taxes paid by employees. I still cannot understand how anyone with even a rudimentary understanding of economics believes this. Taxes paid by employees in the form of income taxes come from wages paid by the employer. The 23% has absolutely nothing to do with those wages. Do the wages affaect the overall price? Yes. But they are not part of the 23% of taxes embedded in the cost of products. The 23% comes from taxes paid by the employer and by the employer alone.
Embedded taxes are whatever the person who did the research said they are. And the researcher who did the study and was paid for it by Americans For Fair Taxation (people who run fairtax.org) has stated clearly that he included taxes paid by employees as embedded taxes to come up with the often quoted 22% number. If you want to define it as something else fine, but the 22% number is meaningless with your definition and is in fact dishonest at that point.