LCWRA and back pay

Hi,

Making a post for my friend who is experiencing some issues with universal credit and LCWRA and any help is appreciated.

For info purposes his assessment period is 21st to the 20th of each month. He first gave his fit note in February 2022. He was awarded LCWRA in June 2022.

However universal credit will only give him the extra money from assessment period 21st September on wards.

They have stated that he is in a relevant period of 90 days from the day of his assessment award in June.
'This means from the date of the award you must serve a 90 day relevant period prior to having any increase in payments for the awarded element'.

However according to the award letter they sent in June and the legislation I've read for regulation 28 (2), is that the 3 month relevant period is from the fit note, not his award.

Everywhere I have searched I have been given the info that it is 3 assessment periods from the first fit note, but he is being told it is only from the award.

I feel like he is due back pay from 3 months after his fit note, however there were a few interruptions between fit notes, these were back dated though, I'm not sure if this changes anything.

Which is correct?

Thank you