Stamp duty is a behavior tax, so it is a tax-paying behavior, and some pay taxes according to the contract amount, such as loan contracts; There are also piece-by-piece calculations, such as warrants and permits.
So it is one-sided for you to say that the unit has to pay sales revenue.
Specifically, you can look at Baidu's knowledge (not well written).
Is the picture a stamp duty rate table? (and taxpayers, etc. , click to enlarge. )
I checked the water conservancy fund on the internet, and I answered this way: this is a local charge, and the name of this charge is different in different places. Some are called flood control security fees, some are called dike fees, and some are called water conservancy funds. Because it is a local charge, it can only be decided by the localities themselves.