Where a shingle roof meets a lower-slope area, the transition requires attention to drainage and compatible roofing details. Continuing the same covering across different geometry is not automatically appropriate.
What to do next
Ask the contractor to identify the roof slopes and the proposed transition assembly. Compare bids on how they treat the junction, not just the two main coverings. Keep the relevant product instructions and transition drawings with the project record.
Related Perkins guidance
Contact Perkins Roofing to discuss your roof and the appropriate next step.