Mixed Tea Service - Gorham and Ellmore - Special Orders?

This set consists of a coffee pot, teapot, lidded sugar, and creamer. The coffee pot, sugar, and creamer have the Ellmore mark and are in the shape of Ellmore’s Victoria but without any of the design work typical for that pattern. The teapot is by Gorham. I assume the teapot was a Gorham special order made to match the Ellmore pieces because it appears to have a Puritan Pattern body with a different lid and base.

This is my first experience with non-standard patterns and mixed makers in one seemingly matched tea service. Are my assumptions correct? Does this reduce/increase the value of the set? Were Gorham special orders common? Was it typical for Ellmore to adjust standard patterns?

Any information or insight is greatly appreciated.

Thank you!