I don't know if you are aware of this, but QueryTracker has a forum. I've been a member for years because sharing information takes a lot of the anxiety and fear out of all phases of the publishing business.
Since I've hung around the QT Forum throughout the entire process of my own road to publication, I've gotten to observe topics come up repeatedly--some causing more debate than others. What strikes me as peculiar is that the most controversial topics are the ones that should be lowest on the list of worries.
Some of these topics are font type, words per page, and how to determine word count. All of these are technical formatting issues. People get really riled up over this stuff. I say, calm down and focus on what is important: your craft.
An agent wants a well-written marketable book. In most cases, he/she won't reject you because of one of the issues I mentioned above as long as:
1) You use a traditional, easy to read font like Times New Roman or Courier New--use only black and 12-point.
2) You research your genre to determine an acceptable length range and using your MS Word word count, stay inside that range if it is possible to tell your story within those confines (Some books just don't fit that box, and yes, there are agents willing to take them on). As for the crazy formula to calculate word count, that came about when writers used typewriters. Spend your time revising and fine-tuning your manuscript. Don't spend it running your pages through a math equation.
How many words per page is, in the end, determined by the publisher. For example, my 75,000-word manuscript was 277 pages in MS Word with one inch margins and TNR 12pt. When it was typeset for the final printing, a different font was used and some artwork was inserted on the first page of each chapter, bringing it up to 336 pages. It all boils down to what the publisher wants it to look like, which is why the word-count in MS Word is fine for submission purposes.
If an agent or editor wants something different, they will specify that on their website, or will let you know. Do your research, relax, and focus on the content of your manuscript.
Of course, I'm only expressing my own opinion, which is that of a traditionally published debut fiction author. Authors who've been in the business a long time have different experiences... Heck, I read an article in which Anne Rice said she still writes in Wordstar (this might have changed since I read it), and her editor has to deal with that ancient word processing software. Would they do that for me? No way!
Perhaps it is because the business of getting published is so frustrating and inconsistent from one agent, editor, or publisher to the next, writers look for concrete rules. I believe this is what causes these heated debates on the boards.
"You MUST do this."
The only "musts" I've found are you must be professional, must produce a manuscript that format-wise follows industry standards (there quite a few options here that will work), and the manuscript must be the best you can make it.
Don't sweat the small stuff. The big stuff brings enough sweat of its own.
Wishing you a fabulous week!