A basic point - the budget of yor project is not the same thing as what you
pay your resources per unit of time. IT is what you pay your resources to
do the actual work that is driectly involved in the project. If you have
Joe who gets $2500 per month and he works on something in your project for 1
hour, doing something else the rest of the month, his cost to your project
really is only ~$16, not his full salary. Let whoever he was doing the
other stuff for pay him for that work out of their budget, not yours <grin>.
And as Rod already said, you should use what is known as a "burdened labour
cost" with adjustments for benefits, hiring and training costs, office space
and utilities, etc, instead of base salary so you are accurately reflecting
the true costs to your firm of doing that project.
Costs in Project reflect the actual costs of doing that project, not the
overall costs of doing business. Unless your resources are all external
contractors, you'd have to pay that resource even if you didn't do the
project at all. What counts from a project costing, roi, etc perspective is
what it costs you to do that work in contrast to all the other things you
could be doing. Even if your costs of doing business don't increase when
you do the project, there still is an opportunity cost to be factored in
based on the fact that you're committing resources here and so can't commit
them there.
