How does 28 day rule for SET(M) apply to premium processing applications

Hi Everyone,

First time poster here. I was granted a partner/spouse visa on 12-Mar-2015. The 5 y anniversary is 12-Mar-2020 which means I can apply 28 days before then - i.e. 13-Feb-2020. My question is how to interpret/apply this date. Is it the date I can submit the SET(M) online or is it the first date I could schedule a premium processing appointment for? Not clear and don't want to get it wrong for obv reasons. Any guidance appreciated.

Best Regards

For SET(M) applicants- spouse visa settlement: DATE of ENTRY minus 28 days.
The biometric enrolment date is irrelevant.
The online submission date must be within 28 days of date of entry.
60 months from date of entry minus 28 days

Thank you for clearing that up. Much appreciated