Alternative to using INDIRECT for dynamic references to other sheets

I've attached a sheet which shows the formulas in one row (of about 100) of a worksheet in a fairly large workbook. This particular sheet culls and organizes the data in the numbered worksheets (about 70 of them).

I'd like to make the workbook more efficient (as it hangs and crashes), so I'm assuming one of the culprits is my liberal use of INDIRECT, which refers to the numbered worksheets in order to get various cell values in them.

Is there a solution for me to use a non-volatile function for this? The worksheet numbers do change from time to time as I add data to my project, if this matters.

Thanks for your assistance.