TimKT,

You can create a table with the periods horizontally and the names vertically. I created it from cell J17 (periods in K17:O17, names in J18:J32). Then, at the first intersection, you can put the formula (note the proper use of absolute/variable references): 
=SUM((GETPIVOTDATA("Hours required",$A$3,"Period",K$17,"Status","Done late","Who",$J18)+GETPIVOTDATA("Hours required",$A$3,"Period",K$17,"Status","On time - done!","Who",$J18))/GETPIVOTDATA("Hours required",$A$3,"Period",K$17,"Who",$J18))
Copy the formula to the entire table, the references will update accordingly. Then, to avoid the #REF!, you can select the cells inside the table, apply a color of font white, then put a conditionnal formatting on the same range if the cell is >= 0 to set the font color to black.