Once an item is scheduled, it leaves Coverage C. The HO-3 lists articles separately described and specifically insured as property Coverage C does not cover, and that applies regardless of the limit for which the article is insured.
The effects:
A covered loss to the scheduled item is paid by the endorsement alone, so there is no double payment. Unscheduled items stay under Coverage C.
The Coverage C limit stays the same. Scheduling $30,000 of jewelry on a policy with a $200,000 Coverage C neither reduces nor increases the $200,000.
Coverage C does not act as excess. If a bracelet scheduled at $5,000 is worth $8,000 when stolen, recovery stops at $5,000.
The practical lesson: review and update scheduled values, because a new appraisal after the loss does not bring the item back into Coverage C.