I'm having a problem with a sumifs function. When I use this formula:

=SUMIFS(Data!K2:K5000,Data!D2:D5000,"=40001",Data! A2:A5000,Summary!$B10)

where K2:K5000 is the value column, D2:D5000 are cost elements (cells
formatted as text in case this makes a difference) and A2:A5000 are Project
Numbers

The formula runs correctly and I get a sum of the amounts that have the cost
element of 40001 for the project number referenced in B10.

When I change this formula to:

=SUMIFS(Data!K2:K5000,Data!D2:D5000,"<40001",Data !A2:A5000,Summary!$B10)

I get a total of all cost elements within the referenced project whether the
cost element is 40001 or not.

What am I doing wrong?

Thanks