Conditional Formatting - Checking If Cells Are Equal?

I am trying to create conditional formatting to ascertain whether values in one table (Table 1) are different from another identically formatted table above it (Table 2) (so each cell in Table 1 has a corresponding cell in Table 2).

If the value in a cell in Table 1 is different from its corresponding cell in Table 2, the cell should highlight in red.

Every cell's corresponding cell is the same distance away.

I tried to put in a conditional formatting for C5 (C5 being the first cell in Table 2), which works, but this breaks and turns to #REF every time i save and re-open the document.