Suppose you had a mage with Secondary Insight and Affinity with Creo.
Suppose you spent a season refining Vim Vis from the Aura of your covenant.
Presumably you would get exposure experience. Don't see why you couldn't put a point into Creo and a point into Vim.
So, could you choose to end up with
2 points in Creo (put point in from exposure, and you multiply by 1.5 for Affinity and then round up)
1 point in Vim
Creo going up means you could raise four Forms and Vim going up means you can raise two other techniques.
So, you could gain 9 XP for spending a season creating vis. So, for 4 seasons, you could gain 36 XP and have a bunch of Vim vis. Admittedly, you probably spread the points less optimally than you would have liked, but it does leave you with a lot of points.