Well, even i am presently working on that issue. but i am working on a much wider roll, i am working on Cost per hour basis, for the call center operations, and for that basic development cost is taken,
for that purpose i have take total yearly depreciation that the company is charging in its balance sheet + a percentage of cost taken as replacement cost, and some percentage as infrastructure maintainence cost, after that i have taken up entire expenses and divided by the no. of total man hours to arrive cost per hour basis,