If the note section in the back of a book is divided between volumes and in volume two the notes start on page b345, is the continuation number used in the TOC? Is there any situation where the continuation page number would be used in the TOC?
I'm not sure how you are dividing the volume or where the note section is in braille. Is the note section also at the end of the book in braille? Is this note section the last item in the book? What comes after the note section? Is there enough material after the note section remainder to comprise another full volume?
The note section is at the back of the print book. However, the notes that pertain to pages in braille volume one go at the end of volume one. The notes that pertain to braille volume two go at the end of volume two. Thus the note section in braille volume two begins on print page b345. BTW this not a textbook, but I am directed to follow textbook formatting.
Formats is not restricted to textbooks, so I think we're safe here. As you know, the continuation letter of continued print page numbers is not shown in the table of contents listing. If this volume contained any other contents item like a chapter or section that started in the middle of a print page and therefore had a continuation letter, that letter would not be listed in the contents and the item would merely be listed on whatever print page number it appears on, regardless of position. The same is true of the notes as there is no direction otherwise in Formats.