I need guide about 2 points and I really appreciate your help.
First, when we use Statical API, what amount of PU and requests is calculated for (512*512 output) for the P10D interval and for one year as well ?
And another question is that
If we use P20D instead of P10D will there be any difference in the number of processing units and requests and the final calculation of them?
The PU calculated will be based on the size of the area (in your case 512x512px) and number of observations within the time period. Typically this would be 100-200 per year, depending on the location. So 100-200 PU.
The aggregation period makes no difference, as the service still has to calculate all the values.