As I mentioned, excluding the bonus, and prior to the dollar surchage, that wasn't really true. The values were perfectly divisible by $2.5.

But if you look at the author's own images, the "Other Amounts" button is pretty prominent. Short of a brand new auto-rebalancer option, what would you suggest? If my claim is true, and that they wanted to have the cheapest transition / software update they could manage, that option would violate that. They essentially changed a table of numbers (I assume) and most of their old UI was reusable.

The next cheapest option that would satisfy your requirement is to blow out all 3 quick options (and eliminate the bonus) and have only an "Other Amounts" path, essentially forcing manual re-balance.