I have this dancer with an amazing base str of 30 and a strength growth chance of 102%!
I do wonder, does this just mean he will definitely grow +2 str per level, or does it mean he will grow +2 str AND has a 2% chance to get an additional +2 str for a total of +4 on a level-up?
It seems followers are supposed to only gain +1 strength on a level-up, but there’s a random chance for yet another +1 strength when it happens. That is cool. In this case my question is does my follower have a 2% chance to gain +3 to strength on a level-up?
IIRC on one of the thrall streams, it was explained that IF you get the first +1, a second random roll will take place, where you might gain another +1. I don’t know what the percentage chance of this second roll is - I don’t believe it’s the one displayed in the UI, that one is for the first +1 only.
I have seen thralls with less than 100% chance in a stat gain 0 points on level up and then gain 2 points on level up. There is always a chance it will gain a point and there is always a chance (and I do not know the numbers but I would assume it is a significantly lower chance) to gain a second point in that stat. But there is always a chance they will not gain a point in that stat at all.
What if it works in such a way that the extra point is roll only from the food bonus percentage? If the percentages do not add up, and they are separate values?
Did they not mention on the stream that it is impossible to get a chance greater than 100%?
So basic 90% and additional +14% will not give 104%, but will trigger two rolls: the first with a 90% chance and the second with a 14% chance (if the first succeeds).
They did not want to mention that food helps to level followers, we had to find it out for ourselves.
If you want to run a test with power to figure it out, you’re setting yourself up to need admin spawning of about 20 of the same named thrall with the same percentages (so hundreds of thralls to sort it out from rng), and test 10 with food and 10 without, recording the number of increases each level. That’s what it would take to get an answer more precise than +/- 20%, and it would be a lot of labor. We’ve been fooled before by coy info, but a hunch isn’t enough to sell me on the need.
If we start to see reports that don’t fit the hypothesis, like a thrall that definitely gained +2 each level for 20 levels or a thrall that gains +3 from a single level-up, excluding perks, then we have something that challenges the existing info.
SO the way i am seeing the rolling is like this, but i could be wrong…
Each stat rolls 1 time. The %by the stat is for that stat only. Which is why they don’t add to 100% combine. If it rolls a “yes” then you get +1 to that stat, then does a RNG bonus roll not tied to the displayed %. If “no”, then that stat gets 0.
This is also why the - on perks sucks. Because over 20 rolls, i could be unlucky and get only +8 on my highest % (it is still rng–weighted in my favor, but unlucky is unlucky). And there is a possibility i can roll a -8 to that same stat, which means i got 0 for the highest % stat.
I would shy away from rerolling the perk but reset the thrall to zero might be an option IF its not a game breaker. Resetting to zero might also be exploited as well. Funcom dev may want to test it internally.
This is why its important some of the dev team play on officials from time to time to see what folks are doing.
If the percentages do not add up, and they are separate values? 
helps to level followers, we had to find it out for ourselves.