need advice on property purchase closing

I need someone to explain how the appraised value is determined for the sale of property here. There is a 2.2% transaction fee charged based on the appraised value. Does the actual sale price affect that value? I have researched this and see that at closing the buyer has to pay for an appraisal and it may or may not be affected by the sales price and the amount on the predial. And is the notary fee based on a percentage of the sales price as well?
Might need someone knowledgeable to pm me so I can ask questions off the board.

If you speak Spanish, go to Catastro and they will give you the appraised value of the property for the area and the particular property in that area.
Any Notario Publico or real estate broker can probably explain the method as they have to keep up with the latest changes.
You can no longer apply artificially low value to properties to avoid taxes and fees, as was the practice in the past.
And yes, everythbing is based on percentages of the avaluo, but if you think it is out of line overvalued, you can ask (but might not get) for a "mejorar" of the Catastro avaluo to bring down to a lower number.