Sum Cells Based on Month

Hello All,

On the attached spreadsheet you have an "Item List", "Order Type", "Quantities" and "Dates" on Sheet 2. I need a program that will look at the item list, Idenfity the Order Type and Month, then Put the Quantity value in the proper Item Type, Order Type, Month slot. If there is more than one then it needs to add them together.

This will be for hundreds of part numbers, but the attached spreadsheet just uses 2 examples. I am toying with the idea of doing a pivot, but I wanted to see if it is possible to keep the data in the original format and do an automatic Sum.

I have several different spreadsheets that I can use this type of VB for, so any help is greatly appreciated.