Thanks a lot, I'm happy more people are interesting in analyzing this :)
I didn't go deeply into the data you're suggesting (but I definitely plan to), but what do you mean exactly by "less than 90% of users switching across projects"? In my analysis, usually less than 10% of users switch across languages. Maybe that's the same thing :)
What I mostly cared about for this data collection is to see whether enabling Compact Language Links changed the number of users who switch, and I'm pretty sure that it did. It's still less than 10%, but it's almost twice as much as it was before the list was compact.