Help me understand tankiness difference between Jugg and Champ pls

I'm trying to understand which is tankier to go against ubers. I'm less interested in the damage differences. When I swap out several POBs adjusting for taunt, fortify, and endurance charges (while keeping everything else the same) I'm seeing mostly better starts on Champ instead of Jugg. Trying to understand why or if something is missing in POB calcs.

I'm mostly interested in playing EA ballista. Is jugg or champ really significantly tankier and why?

I used several jug and champ builds and did swaps to look at the numbers.

ty!

It mostly depends on the armor numbers. Jugg can ignore spell suppression and evasion if you just stack armor + endurance charges. At low armor champ is better, high armor jugg wins.

Also it depends on where are on the tree the skill points you want to take. For explosive arrow champ is better because it's closer to elemental equilibrium.

For any stacking armor and/or str jugg is better. For ranged characters with no shields champ is better because of the flat fortify.
For shield users usually jugg is better onless you need to go right on the passive tree, with some exeptions (like herald of agony)