SD FAT32 file system

I’m implementing the SD FAT32 file system without CPU involved so i took using 8GB SD card and i formatted as FAT32 and i check the FAT32 structure fields values
And again i took 16 GB SD card card and i did same which i done in 8GB card that time i got some fields values were different So could you please tell me how these values will vary wrt disk size and what is the calculation to calculate this?

Thanks And Regards,