Thank you for the question, Melissa!
First thing's first, I do not know of any rule or guideline that addresses this particular situation.
It seems to me that the best way to preserve print's up-and-down comparison between numbers is to present the numbers with tactile lines used for the boxes and arrows, with one line texture for blue and a second line texture for red.
If you absolutely cannot do that, then you might design formatting inspired by Braille Formats §13.9.3, which tells us to transcribe a poem that contains stress, scansion, or meter marks twice and to use a transcriber's note like the following.
The numbers are first shown without any place values highlighted, and then they are repeated with the appropriate symbols. Blue typeform marks the numbers that are the same, and red typeform marks the first numbers that are different. Symbols used:
.=@#1 Blue typeform word indicator
.=@#' Blue typeform terminator
.=^#2 Red typeform symbol indicator
Does that help?