INDEX/Match (average a range of specific cells)

Hi guys! I'm trying to get some help on a formula on Google sheets. Essentially what I'm trying to do is get an average from a range of specific cells using Index & Match to locate the data within the second tab of the spreadsheet. However using excel via Google the results aren't populating which makes me assume something is wrong with formula I am creating.

I am building this directly on Google Sheets.

1st scenario: 7 day pre-average from the selected start date.

=iferror(average(INDEX(Orders!A$2:FI$964,match(A2,Orders!A$3:A$964,0),MATCH(B2, Orders!A$2:FI$2, 0):INDEX(Orders!A$2:FI$964, match(A2,Orders!A$2:A$964,0), MATCH(B2, Orders!A$2:FI$2, 0)-7), "n/a")))

2nd scenario: average from start & end date

=iferror(average(INDEX(Orders!A$2:FI$964,match(A2,Orders!A$3:A$964,0),MATCH(B2, Orders!A$2:FI$2, 0):INDEX(Orders!A$2:FI$964, match(A2,Orders!A$2:A$964,0), MATCH(C2, Orders!A$2:FI$2, 0)), "n/a")))

Access to the Excel doc: https://docs.google.com/spreadsheets/d/1JAwT_TyCdD5gLFCp344f1-_oZYBCAOQikmGOkFNaPP0/edit?usp=sharing

Any help is appreciated! I am still trouble shooting.