Return scroll or go for it?

I'd say just go for it because I don't think the Return Scroll works that way:

When applied to a piece of equipment which then has an upgrade scroll successfully applied, the Return Scroll allows you to decide whether you want to keep the new stats or revert back to the original state (including the upgrade slots). This is useful with Chaos scrolls, where a successful scroll attempt may still result in worse stats than you had before.