I think the reason that a lot of people (the jury too, presumably) scratch their head and struggle to understand the material difference is because, regardless of whether he was a spokesperson for the Clinton campaign or is just a lawyer who works for the Clinton campaign, his involvement with the Clinton campaign is the same.
If his political affiliation/background/associates would influence how investigators handle his information, then that wouldn’t vary regardless of what he may have said or texted about whether he was on the clock when he went to the feds. The bias in his allegations, to the extent it exists, is still basically the same.