4K - Price Quotation

Hi all,

I need your help please,
Our studio (PitchiPoy) is in the development phase of 8 films (each film is 120 second long). The final films will be projected in a museum. Nothing final yet - nor the look or the animation technique. Our style is less realistic - more of an artistic nature/textures/combination of techniques
Our initial price quotation was for standard full HD. Now the client asks me for a 4K price quotation.
Any one had any experience with this kind of resolution in Blender?
As a ball park number, my gut feeling (hardware, slower workflow, render, compositing) is a 30% - 40% increase to the original quotation.

A detailed answer would be highly appreciated.
Thanks in advance.