I've edited my post to make it less confusing.
SPQR is correct about taxpaids having denominations in quantities of a product rather than a monetary amount, but that changed over time. Example: the 1st tobacco taxpaid stamps were denominated in ounces or pounds of tobacco, and the tax rate. But later issues of tobacco taxpaids indicated the actual amount of tax paid.
Attached are examples of three early taxpaids. Not shown to scale. The first stamp, for distilled spirits from 1868, is actually quite large.

This stamp is actually the size of a postage stamp, from 1868. Two ounces, "Class 32 Cents" (the tax rate):

This stamp indicates the actual amount of tax paid by the stamp, from 1869.
