Why my formula is showing error - Inconsistent calculated column formula in MS Excel?

Question

My formula is showing error: Inconsistent calculated column formula. But still its working and returning result as expected.

Formula:

=IF(B7="","",IF((MINUTE(M7))>=15,TRUNC(HOUR(M7)+MINUTE(M7)/60)+1,TRUNC(HOUR(M7)+MINUTE(M7)/60)))

I'm using Microsoft Office 2007. Please help.

Solution

That's because the formula on the previous row/column is a bit different. This is what Microsoft says about it:

Calculated columns in Excel tables are a fantastic tool for entering formulas efficiently. They allow you to enter a single formula in one cell, and then that formula will automatically expand to the rest of the column by itself. There’s no need to use the Fill or Copy commands. This can be incredibly time saving, especially if you have a lot of rows. And the same thing happens when you change a formula; the change will also expand to the rest of the calculated column. A calculated column can include a cell that has a different formula from the rest. This creates an exception that will be clearly marked in the table. This way, inadvertent inconsistencies can easily be detected and resolved.