Trying to use wildcards in a sum array formula

After receiving some great help with an array formula, I have run into another problem - using wildcards.

In the attached workbook on sheet1, I have the product numbers sold in quantities for each day. On sheet2 I am trying to sum these in a report. This works fine if I want to see which product is sold (Row 1) but I want to drill down at the substring level as this corresponds to a particular product configuration, and I want to see how many of this option have been sold.

What I want to do is hard code something like '?????A0?????????" or ??????????????1A". Better still, I would like to be able to type into row 1, A0, and just hard-code the position in the substring that these would be analyzed, if that makes sense.

I have tried hard-coding into my sum array formula but it returns 0 results.

If anyone can help to get me there I would be very grateful.

Thanks in advance.

Thanks MarvinP. I am constrained to a certain format. Thanks for your response, I appreciate it.

Sixthsense, thanks, I was able to use this to suit my needs. Really appreciate the solution.