OmniOutliner Sync with OmniPresence

Can anybody provide insight as to whether when an OmniOutliner document syncs through OmniPresence, does it re-transmit the entire file, or does it just transfer the deltas?

Basically, will continuous sync of a large file with attachments eat a lot of data, or only a little?

I just found this answer from 2015:

I assume things haven’t changed? This is a real shame if so.