Some IO will give you the 60 days before you've used your 30 days extension, but i believe it's one of the other, not both.... And again definitely varies from IO to IO. But in some cases, they will grant you that
it depends on your visa. If you're visa exempt, you get 45 days 30 with 15 days extension for quarantine and tr visa you get 60 days with 30 day extension.