How much attack does Miracle Chaos scrolls give?

Chaos Scrolls do not give attack. They only increase or decrease existing stats on an item. Since the super Zakum Helmet does not actually have any attack on it, It will not add any attack to it

For reference:

Chaos Scrolls can add or subtract up to 5 of a stat
Miracle Chaos Scrolls can add or subtract up to 10 of a stat.