Mind that case:

The placement of the lense doesn't seem to make sense here. That's what this is about.
Proposed operation:
a) chest not full -> Item gets (colored and) stored in the chest. (As it works right now)
b) chest full -> Item gets colored since it "wants" to go that way but since it can't go there the logic is looking for another movement direction. Result: On full chests the item gets colored and moves on (thus you later can decide of which items you already have enough and which items just weren't sorted.

Why not just place a clay pipe inbetween the diamond pipe and the chest so the items will try and insert into the chest. If it is full, put a lens on the direction it would go if it is full and deal with the painted item from there

It just seems rather unnessercary as we can do that now with the tools we already available and adds unnessercary complexity

Typical usecase (8 sides like them -> 8 * 4 * 5=160 pipes):

Why not do a design like this:

and the diamond pipes gui look like this:

Its tilable, faily simple and seems to do what you want it to do without any modifications to the mod?

This was implemented a while ago in 7.99.x. I'm not sure which version it was first introduced in though.