.. are you going to argue with an established, reputable ad agency, if they say they want a line-item quote, regardless of whether you feel it is really necessary?
You mean, if they wanted a line-item list, listing what camera system I was going to use, what lenses I going to use, what lights I plan on using, modifies, number of stands, tripods, computers, software, back-up systems, etc, etc - as well as a full break down of my travelling costs, my estimated pre-production time, my photography time, my post-production time, number of assistants I planing on use, their costs and expenses, etc, etc, etc !!
If so, I would probably be wondering what they were actually wanting from me - because this would sound more like a work made for hire type of agreement, as opposed to me to give them a price, for me to produce and then provide them with my images for them to use.
So I probably wouldn't argue with them - but would instead, just ask them what they actually wanted me to provide them with - and then simply quote them a price based on that information. Which in the end, if it when ahead, would then tally with the words & boxes ticked on this form:
Not saying I'm right - but that's what I do and how I work with most clients - including ad agencies & editors of magazines throughout the world.