I'm looking for a way to use SharePoint efficiently such that if users in 10+ sites update an Excel document, it would automatically update that information on a Excel doc of a parent site.

Currently, I have 10+ Excel workbooks that are externally referenced to a parent workbook on a shared drive. The parent workbook is automatically updated per changes in the 10+ child workbooks.

I can't use SharePoint lists because its structure is limited to only 1 set of rows and columns, while the workbooks have numerous tables per worksheet that each have different row/column values - meaning: multiples lists would have to be created per each table which would be inefficient to navigate and configure.

Does anybody have any insight on a possible solution with SharePoint Excel Services, PerformancePoint, or Business Intelligence? PowerPivot isn't really an option either because it requires installing the add-on for each Excel 2010 user involved.  Thanks

Check if this can help you 

https://support.office.com/en-za/article/Synchronize-a-list-with-a-spreadsheet-program-bfb2ea48-6118-4fa9-abb6-cced9424e5d9

https://support.office.com/en-gb/article/Synchronize-a-SharePoint-list-with-a-spreadsheet-program-d4337a01-2be4-43b5-bb42-28aefe64eafd