Sumif from Table - Salary Calculations

Hi All - can someone help me install a sumif formula into C27 that will add up all from the table above it? The problem I was having is that there is a step-up schedule that doesnt have any ryhme/reason - its different for different position, and not set by date.

Please help if you can!
Thank you so much

Payroll Sumif Help 4.16.13.xlsx

Thanks for looking at this FDibbins

The expected answer would total all salaries that are in effect after a given date, i.e. cell C26 (4/1/2013), and divide by 12 to get the monthly payroll expense

I have the following in Cell C27 =SUMIF(E7:E22,">="&C26,D7:D22)/12
The only problem is that it doesnt incorporate a step up in salary -

Does that help any?

Thanks

I was able to break it down some with this... but still cant drag the formula all the way down/across....

Payroll Sumif Help 4.16.13 v.2.xlsx