Enchantment Power Bonus issue

So far I've seen nobody point this out anyway but for some odd reason I've noticed while making my custom bookshelves mod that with the enchantment power bonus, Setting this as 2.1, 2.2, 2.3 etc is no different to setting this as 2. Basically, decimals change absolutely nothing yet its still an option? Not sure if I'm missing something but I did spend a good 5-10 minutes testing this out.