I don't know any method to count the time which engineers waiting on the computer, but i've found interesting article: Build Your Own Render Farm
], where you can find solution...
Building "render farm" you can expect the following profits:
A local render on one of the school’s 2-GHz Dell workstations, which are equipped with nVidia Quadro4 XGL cards and 512MB of RAM, draws out the 800-frame piece in 52 hours. Using a one-worker farm, our time shoots up to 104 hours-unsurprising, considering the age of the machine. But after adding six more workers to the farm, the same render clocks in at just over 13 hours, more than three times as fast as in pre-farm days.
[EDIT] The second look at the problem... [/EDIT]
] you can find information that you can programm AutoCAD 14, 2000-2010 software, for example writing custom function which can count time which is neccessary to render project.