Not terribly useful to those of us running troupestyle, neh?
I like Erik's model, but then, I like Metacreator's model as well.
I prefer Jonathan's model.
In those rare cases that an Affinity is gained in-play - recalculate the XP total to get the right result (so NEW TOTAL * 1.5 = OLD TOTAL). Yes, it means that XP is technically lowered, but not really. And you can then proceed to calculate the art/ability score with no hassle as the character gains more XP.
Either that or collecting fractions is how I prefer it.
Well, I take comments from the table under advisement. But I don't find it particularly compelling to add an affinity after any old Twilight Episode. Maybe after several in a row, particularly if some have turned out negative. And I doubt a troupe, as a whole, would be handing out affinities on a regular basis, but I might be wrong about that.
As it happes, consensus generally prefer handing out odd-but-potentially-useful out, rather simple and obvious bonuses.
That doesn't change the point though.
I have no idea what your point is, at this time. I pretty much said I take consensus of the table. So, remind me, what is your point...
I'm sorry, that's not what I read.
To me, there seems to be a significant difference between
Indeed it looks like the difference between Ankh Morporkian democracy* vs Athensian direct democracy.
..but I may well be simply over interpreting.
You are.
My "solution" is to not be bothered by an extra half of an xp a few times per year (often times twice in the same season if they're getting exposure through lab work). It is what the rules say, it generally makes the players pleased, and affinity while being a fairly powerful virtue still isn't game breaking.
The problem folks have with it could (I suspect) be better solved with a change in perspective rather than a change in rules. Of course that doesn't help metacreator at all.
I said it's a pet peeve, I never said it was rational... 
Rereading my post, I don't think I put enough IMO style stuff in it. It comes across as me telling you how you "should" run your game.
I just wanted to tell folks what worked for me, not insinuate that if they did things differently they were wrong.
Thanks, Jonathan. I hadn't thought of that. It will serve my needs.