what I am referring to is simply there was a number based on what has been paid out to each department specifically(wages) over the past several quarters, that is what my point is...
First, companies deal in expense and not just wages (which are merely one factor in expense). While the company may have a budget for specific items - like F/A expense - there is no guarantee that the amount budgeted won't be higher or lower than the actual expense for the year. After all, the company can't just say "We've spent all we budgeted so we're not going to pay you the rest of the year." Conversely, you won't hear the company say "We've got money left over from what we budgeted, so the surplus will be added to your next check."
Second, the BTS form 41 data (which was apparently used by the author of the study) is also expenses and not just wages.
Third, even the BTS data doesn't break out F/A expense - only pilot and F/O expense is broken out. There are 3 other categories of flight ops personnel expense - other flight personnel, trainees/instructors, and personnel expenses.
Fourth, when the carriers file their Form 41 data with the BTS, they don't all report various expenses the same way. For example, US reported the cost of pilot training as a separate expense while HP reported $0 pilot training cost (presumably putting training expense in another category). So if you used the pilot expense numbers to compare pilot costs at those two carriers, you'd be comparing apples to oranges. The same could be true for any comparison of a specific employee group.
Without access to a company's books, it's impossible to make a valid comparison between the wages of an employee group - the specific data needed just isn't available anywhere else. The next best, if you're talking strictly about wages, is to compare the pay scales. Most of the other factors that affect the cost of having the average F/A (or pilot, mechanic, whatever) on the payroll are demographics (the makeup of the group) and contractual. Using the pay scales eliminates the effect of demographic differences, leaving only contractual differences - one group may have better benefits in areas other than pay (like vacation, reserve system, pension contributions by the company (and a 401K is a form of pension plan), etc. while the other group may have elected to get improved pay at the expense of those other items.
Last, it's somewhat surprising that the OP has such faith in the numbers in the report but then neglects the author's "Average flight attendant wage/salary" numbers - perhaps because it disagrees with the OP's premise that NW F/A's make more than DL F/A's.
Jim