Why are the site values from the AFAD map different from the site values calculated using the Offline option in the TDY wizard?

Spectra values ​​obtained by using the Offline option in the TDY wizard are calculated by the program. Since AFAD and ideYAPI use different algorithms, the values ​​are not exactly the same. (The earthquake results obtained by using the Online and Offline options make little difference.)
If you want to use the same values ​​on the earthquake map, you can enter the spectrum values ​​(Ss, S1).