verb (used with object), o·ver·rat·ed, o·ver·rat·ing. to rate or appraise too highly; overestimate: I think you overrate their political influence.

What overrate means?

transitive verb. : to rate or value (someone or something) too highly By grossly overrating the danger from Communist agents inside the United States, the scaremongering of the House Un-American Activities Committee boosted the impression that Communist monsters in general were a mythical breed.—

Is it storewide or store wide?

store·wide

adj. Involving, applying to, or occurring throughout a whole store: a storewide sale.