i have to do that a couple of times a week, detailed stuff for big money contracts, its pretty easy once you know how, the main part is making it look good while still understandable.
ones i do has to be sent to the head of sales at Tesco/BP/Burgerking/Asda/VW/LittleChef/etc so they gotta be good or we dont get paid.

im also top class at totaly falsifying it to get far more money than we deserve too