Hi Felix ,
I may be wrong , but my reasoning would result in a different daily quota.
When nothing has been sold as on the first of July , you should still have a daily quota figure in E1 based on the weekly quota figure entered in A4.
When a figure for the day's sales is entered in B5 , the daily quota in E1 should reflect this ; thus , according to this , the correct formula in E1 should be :
=($A$4-SUM(B5:H5))/COUNTBLANK(B5:H5)
Narayan