Originally Posted by twobob
I have experienced mixed results with that particular modification as documented here https://www.mobileread.com/forums/sho...postcount=1046
Works flawlessly in certain cases, I can't speak to the latest release as I haven't tested it recently. sufficed to say that is a tricky kettle of fish.
If I'm reading the post you referenced correctly, Twobob (and I may not be) it agrees with what I'm saying in my earlier post, i.e., with azw3 files, the only JBPatch font sizes that work are the ones that match the default sizes.....so in your example, the default sizes are 7, 8, 9, 11, 13, 16, 25 and 37, and your active sizes in JBPatch are 4, 5, 10, 11, 15, 16, 20, 21....so I contend that the only ones that will work are the ones which are in both lists, ie 11, and 16.
I tested this (admittedly, only on one book, and only with one font, so not particularly extensively) by trying all sizes, in single steps, from 5 to thirty-something, and the only ones that worked on this particular azw3 file, using JBPatch, were the ones that were already in the default list.