calculate workday before x month

Hi Everyone

I have a table of some vacancies for a company. I only require the staff for those vacancies to start working from a certain month, which is different for different employees. For example I might need one in Nov but the second member of team that I require I might not need until January 2008. Where I dont need the staff the data within that month column reads 0.0, where I need the staff part time it reads 0.5 or where I need them full time it reads 1.0.

However, It takes a certain number of working days to find an employee. This depends on the type of employee I want to find. The type of employee and the time it takes (the number of working days) are stated in a table underneath (second table).

Therefore I want to be able to know when I need to start looking for an employee in order to have them ready and employed and working for me as soon as the month in which I need them arrives.

e.g. if I need an employee in Nov 07 and that employee is a Contractor (and according to the table it will take 20 working days to arrange for that employee) I want excel to calculate a date (in colummn C) that number of days (20days in this case).

However, for example if its a permanent I want excel to calculate that date to 60 working days prior the month when they are needed. (as mentioned the days and type of employee are mentioned in the table in the worksheet, 4 maximum combinations).

The month from which I want them to start working from is indicated by placing a 0.5 or 1.0 in that column (cell). I am only interested in Excel working out a date x number of working days before the month in which I FIRST need them so please ignore any months with 0.5 or 1.0 thereafter. I just want it to look for 0.5 or 1.0 in whichever month comes first and calculate a date of when I should look for that employee based on the time it takes to find that type of employee as stated in the second table below.

I hope I have not confused you all. I am sure its simpler than I make it. I would really appreciate your help in this matter.

Many Thanks and Regards