Is Shield Block overflow affected by attacker level?

[Stengel]

The overflow of SB block bonus into crit block bonus depends on avoidance. Avoidance is reduced against attacks made by higher level attackers.

Thus the question: Do we get exactly as much crit block as the SB buff tooltip says or is it less against higher level attackers?

[Andenthal]

The overflow indicated in the tooltip is versus an equal level attacker - just as your character sheet values display against an equal level attacker. Also, I'm pretty sure it only shows integer values (probably rounded down).

[Quinafoi]

Naturally since you have 0.2% less block per level the attacker is higher than you, the amount of overflow would be less by this amount as well (because its no longer overflow). Against a level 88 (level + 3, raid boss) 0.6% of your overflow is not actually overflow because it needs to cap block first before it starts adding to critical block.

[Andenthal]

It will be 2.4% less versus a level 88.

[Stengel]

It will be 2.4% less versus a level 88.

How do you know? Did you test it or are you just guessing because it would make sense?

[Andenthal]

It's because you need to fill an additional 2.4% of the combat table against a raid level mob. It's the same numbers we've been using for 4+ years now.

[Quinafoi]

Yes, I forgot to include the other avoidance factors when I should have since block is the last factor on the combat table it would actually make up any shortage in all the other values before hitting the overflow point. My bad.

It's 2.4% because you lose 0.6% miss, dodge, parry, and block. However the block that was over the cap (additional critical block) would be converted back to normal block such that no attacks are unavoided or blocked (the "unhittable" threshold). That 2.4% is actually the maximum you could lose once you exceed that threshold.