Backdating and 7 day waiting period

A jobseeker claims UC on the 20th, waiting period 7 days, so the AP starts on the 27th, and away they go.

Had they also sought backdating worth 12 days on the 20th (that is then authorised by the DWP), then I assume the claim is deemed to start on the 8th, waiting period runs 7 days, so the AP starts on the 15th - us that right?

Apologies if this is obvious to everyone else, or has already been discussed!

Yep looks right to me, the backdating should be applied to the date of claim not the date after 7 waiting days if applied. Well done on approved backdating, have sought MRC on a decision that it regs did not allow it.