You spotted something significant which no one else did!
I think your explanation for why there are 2 layers of scrolls is correct. The 2 levels of scrolls is an elegant solution.
So that no one else gets a chance to broadcast your find/observation as their insight, I have done a post on Instagram, clearly acknowledging that it was your find.
Here is a link
For those who cannot access Instagram below are some of the images I used to highlight 992234177's find.
I think that the arches have been lowered slightly for Queen Camilla.
Congratulations again 992234177!!