Jolie Gentil in Large Print

I have been adding large print editions for the Jolie Gentil cozy mystery series, something important to me because my mother had limited to no vision for many years.  She largely listened to books on tape (long before the digital age), since holding a book was also difficult for her.  The Library of Congress still operates the National Library Service for the Blind and Physically Handicapped (NLS), which lends Braille and some specialized audio materials free of charge to those whose need is certified by a designated professional. While there are no audio recordings of my books (yet), making them available in large print does permit more people to read them.  Unfortunately, when the type is larger there are more pages so the price must be higher.  I did the first book Appraisal for Murder (at Create Space or Amazon) in the same 6 x 9 size as the original, and it was more than 400 pages.  I wised up and did the second, Rekindling Motives, in a 7 x 10 size (at Create Space), so it stays in the 300 page range and I can price it a bit lower.  I'm experimenting, and may eventually do all in the 7 x 10 size.  To keep the prices reasonable ($9.99 for Rekindling Motives) the books are only for sale via Create Space and Amazon.  They would have to be at least $2 more to be available on other sites, and that does not seem reasonable to me.  (The cost would have to be the higher price on Create Space and Amazon as well.)