Does the subject even make sense?

I have a cell H20 that when the spreadsheet is blank is coloured yellow to
highlight the fact that it has a special purpose.

When the spreadsheet is blank the number 0 is displayed in this cell.

It has Conditional Formatting applied to it to turn the cell red and display
the word FAIL if the summed result is between 1 and 79.99

For 80 and above the cell is coloured green and the word PASS is displayed
in it.

All great so far...

However the summed result in this cell H20 depends upon the result of
another cell H17 that in turn depends upon the input of 5 other cells
C12:G12

I would rather H20 does not change colour until all of those 5 cells C12:G12
have data in them as it would be wrong to display FAIL in a red cell until
the result of all 5 cells are input.

Does that make sense and is this even possible?

--
Regards,
-pp-