I liked the design on the original, but the spaces for the extra bits went all the way to the bottom. Maybe it wasn't supposed to be functional space for bits and was intended as a design feature.

Simple remix to shorten the spaces for the extra bits so they don't fall to the bottom. 3 of the slots are about 10mm deeper to accommodate longer bits.

The only issue I have is the spaces are tight in that it's hard to remove the extra bits. Maybe resize up to 101% before printing? I suspect they will loosen over time as bits are inserted/removed.