FDA Approval, page-193

Ok. I think now I understand why everyone is confused about SAMR registration. Will try to explain.
SAMR is issued for four years for a certain product manufactured on a certain factory. It must be renewed every four years. Synlait received its first SAMR for a2 china label in September 2014, then renewed it in September 2018 and now it must renew it by end of September 2022 (unless there are some exceptions, maybe covid related, which I'm not aware of, that will allow to extend this deadline). Once it's renewed next renewal will be September 2026.
Now, from February 22, 2023 new standards will come into force. What does it mean. It means that from this date all currently registered products that already comply with these new standards will continue with its current registrations ("automatically reregistered" if you wish) and don't have to do anything. If registered (at time when new standards come into effect) product does not meet those standards they must go through another process of re-registration.
So, this September a2 will re-register a2 china label that will comply with upcoming new standards and as result they won't need to do anything came February. If for some mysterious reason they decide re-register non-compliant product they will be forced to re-register in again after February (I'm sure they are not that dumb).
Hope this helps and is not too complicated