FOR INFO ONLY
A friend had to change from 1 year m/e O by marriage to 1 year O
extension by 50+ (not for us to reason why).
His O is still valid but has been on amnesty since early April due to border closures after his last border bounce.
IO said no problem in changing (financials permitting) but the 1 year commences from the expiry date on his last border bounce. The 60 day extension used covering Apr-June doesn't count , neither does the application date or the amnesty/grace period. So in his case he only received just over 7 months.