This may be difficult to explain but am going to try :)

I need to track "Liaison Costs" and "Sorting Costs" by
month. I also need to compare "Liaison Costs" to a
budget and generate the difference on the chart for the
given month, at the same time displaying a stacked bar
that shows the "Liaison Costs" and "Sorting Costs".

For example:

Jan Feb Mar
Liaison Costs 15,000 16,000 9,000
Sorting Costs 6,000 15,000 11,000

Budget 15,000 15,000 15,000

So now I need to plot the charges for sorting and
liaisons as a stacked bar. I also need to compare the
liaison costs vs the budget and display the difference.

I can display it so that the liaison costs are on the
bottom of the stack bar and then draw a line across the
months to represent the budget of 15000. The part I am
stumped on is whether it would be possible to now display
the difference along the "line" that represents the
budget (or anywhere else on the chart for that matter).

Is this possible and if so, any direction is most
appreciated!