I remember, the few years I supported Microsoft Project as a Tech. Support guru, we frequently had to repeat to the users, "MS Project is not a manpower solution."
The confusion comes as people schedule resources for each task, and expected manpower to follow the tasks hour for hour. Unfortunately, slack between a resources normal workday, and their task assignments was never tracked or flagged by MS project, at least through 1998 versions that I worked with.
The most elaborate solution I attempted to solve this shortfall was merging Excell spreadsheet calcs, thru visual basic back ends. The brickwall him me at Duke Power headquarters in San Romon, when centralizing master scheduals with all the regional resources, since corpororate accounting would not release permissions for linking payroll databases with Microsoft's proprietary and un-secured softwares.
Duke Pwr. did a little research, found most corporate clients using Project Primavera, a sophisticated Project Mgmt. solution that had been around much longer, and which accomplished much of my back-end efforts securely thru simple menu's than any scheduling monkey could do by themselves.
Duke was one of many that cancelled MS project, and similar back-end technicians. That was a career shedding event for me, which ended some miserably hard times finding work.
The basic task, resource, project cost, & critical path functions MS project performs is intended for field mgmt. users; that simple design was never intended for manpower scheduling, payroll, or the need for back-end technicians.
I never believed MS outlook's calendar linking adequetly addressed the payroll and manpower needs of most clients. Intuit Quickbooks, or BofA's new online payroll tracking for clients would come closer to that kind of solution.