yes offset % is percentage of the offset of the current zoom.
so 50% @ 1/16th (zoom) would be 1/32nd
now if you zoom in, it wont be offset (so 0%) , since it will now be on the appropriate step
(but imagine 55% @ 1/16th, when you zoom in to 1/32, the step will have a 10% offset)
when you have more than one note on that step, that have different offset %,
then it shows the min and max offset.
I think your other question, seem to revolve around a common question,
which is basically can I work with a grid that is not divisible by 2.
(this is required if you are going to use quantisation)
no - you cannot set a ‘triplet grid’ (common request), as you can in a daw,
thats because the pyramid allows you to have customisable time signatures per track, which combined with zoom - which allow you to do something pretty similar but for a different ‘perspective’
its a bit of a complex topic, so Id refer you to other answers on the forum (search triplets 
)
I think the latest is perhaps the clearest… but there are a few that go into other ways, and also deeper into the topic. https://squarp.community/t/triplets-workflow/655/21
really we would need to see before and after, and what you did exactly.
if you used quantisation, a lot of this depends on the grid size you used.
as its going to just move anything > 50% to next note (0% offset) and remove offset if < 50%.
unfortunately there is no ‘quantisation amount’ on the quantisation fx,
but you can kind of do this manually by selecting groups of notes (or all notes on track) and then just changing the offset encoder of all notes, but a particular amount.