I have a bow with 5 enchantments , Power V, Unbreaking III, Infinity, Punch II, Flame , but it seems depending on which order the enchantments are in the book, will depend on whether it will enchant a fresh bow or not. I've enchanted several bows before with these enchantments, with no issues, the order of enchantments is different on my original enchanted bow.
The first screen is my current enchanted bow, and the others are me trying to enchant a fresh bow with a book i created with all the enchantments. I have done it this way several times and not had any issues with "too expensive" until now, but i'm not sure if the enchantments have to be in a specific order to stack correctly and not get the too expensive warning.