A valley can concentrate runoff at a particular roof edge. Overflow or staining below that location may require review of both the valley and gutter arrangement. Cleaning one component may not resolve the entire issue.
What to do next
Document the flow pattern safely during rainfall if possible. Ask the contractor to explain the cause and proposed correction. Compare changes to the roof detail and drainage system separately so the scope does not rely on a generic gutter replacement alone.
Related Perkins guidance
Contact Perkins Roofing to discuss your roof and the appropriate next step.