Grim Tools does not shown proc chances correctly. In-game values are different and boosted by skills cooldown in particular. More here Bysmiel's Command (% Chance on attack) differs between GrimTools and InGame stats
For example Judgment / Warcry will show 100% proc chances for most devotions in -game which is not reflected in Grim Tools.
My favorite not obvious proccer is Silvercore Bolts because it will show like 15% in Grim Tools whereas in game it’s like 50% and it’s for just 1 projectile so for 5 projectiles it’s ~ 97% 