The normal calculation for a task's budgeted costs is the sum of the
man-hours of work times the hourly rate for each work resource on a task
plus material resource costs plus any fixed costs entered in the "fixed
cost" field. As actuals are posted, the same calculation is usually done to
come up with the actual cost, based on actual hours worked and materials
consumed plus fixed. These are bottom up calculations, of course. It sound
like your "estimated costs" are top-down instead, something I usually think
of as an allowable distribution of revenues and capital. Bottom up
estimates are an estimate of what tasks are LIKELY to cost you
out-of-pocket while the top-down budget is an estimate of the maximum per
task you are going to be able to spend. Hopefully the former is less than
the latter. There's an extra $500 after my bills are covered that I can
spend on something new, that sort of thing. But Project's cost estimates
are more like "I need to buy a new suit and the only one that fits properly
costs $400." That says nothing about whether I can afford it or not, only
what I'll have to spend if I'm to get it. If my discretionary income for
the month is greater than the estimated costs, I can get my new suit - if
it's less, I can't.
It sounds like what you're really asking is to have the ability to compare
the project's allowed expenditures by task (your estimates, in other words)
on the one hand with Project's calculated bottom-up cost estimates, and
later the bottom-up calculated actual costs as well, on the other hand to
see if you can afford the suit this month <grin>. So why not grab one of
the user-defined empty cost fields to hold those allowed budgets and use
another calculated field to do the comparisons. Take, say, [Cost1] and
rename it "Budgeted Cost" and input your estimates. Meanwhile Project will
calculate [Cost] based on the schedule and [Actual Cost] as you input
progress data - hours of work performed etc based on hours and resource
rates. Then it's straight-forward to set up another calculated field for
[BudgetedCost]-[ActualCost] or whatever other calculations you may need.
Will this achieve your goals or have I misunderstood?