This sheet has three columns .

Column L has this formula =SUM(J18+K18) =SUM(J19+K19) =SUM(J20+K20) etc

Column M has no formula and is where data is entered

Column N has this formula =SUM(L18)-M$5:M18, =SUM(L19)-M$5:M19, =SUM(L20)-M$5:M20

Everything is fine except column N which subtracts the cell the day the data is entered but following day column N is ignored and the figure entered previous day is not even taken into account.

Here is the sheet causing the problem