Model a refinement as a replacement, not a free stat

A reroll removes the old refinement line when it adds the new one. The item rating alone does not show whether that exchange helps the content you are building for.

THE PRACTICAL ANSWERRecord the old line as a loss and the new line as a gain, then compare the resulting survival and damage totals for the target mode.

Open the full game screen

Extracted from the game screen

What the game says

The recorded Endless Barrage bracers show Damage Bonus +2.69% and Crit Bonus +17% as their current Lv7 refinement lines.

Both HP gems are still socketed: HP +65,673.9 at Lv6 and HP +48,160 at Lv5.

The observed HP decrease came from replacing the former HP refinement—not from removing either gem.

USE THIS RULE

Make the change deliberately

Record the old line as a loss and the new line as a gain, then compare the resulting survival and damage totals for the target mode.

AVOID THE WASTE

Protect the resources already spent

Do not add the new roll on top of the old one in a simulation, and do not judge the change from Base Rating alone.