Toyota aftermarket soft-tex seats and color options

A dealer told me that I can replace the fabric seats (heated) with leather seats (heated) aftermarket. But the color has to be the same as the fabric color. The seats are possibly the same material as toyota factory. They are installed by a local supplier to the dealer.

Does anyone have a different experience or opinion on why the same color is required?

Does anyone have experience with aftermarket seats?

(this is for a Rav4 Hybrid)