Initially, the grid is filtered by "Is FTE? = True". It shows 20 lines. The sum of "Hours" should be 800. But the footer shows another value (depends on the random logic which you've implemented). See the attached screenshot.

Then, when changing the filter, the correct sum is shown.

But I need the correct value initially...

Re: I've just found out that using the OnRead event instead of the standard data binding solves the issue. Better said, it's a possible work-around.