Do you understand how microBENCOST does the calculations or is this something that you are not usre about. There are programmes designed to do similar calculations but they may not use the same methodology as microBENCOST so it's important you understand how the calculations are carried out in order to do an appropriate comparison.
I have do extensive cost benefit analyses before in Excel and I know of at least two cases where an automated product based on VB and Excel have been produced for clients to undertake standardised cost benefit analyses, although I may not recomend this approach myself.