I have some conditional formatting to check that a value in column CO
does not match the value in column A, and that cell should not be
blank.

If I check against column A using
=CO31<OFFSET(CO31,0,1-COLUMN(CO31))
it works fine.

If I check the cell isn't blank using
=CO31<""
it works fine.

BUT if I combine both and use
=AND(CO31<OFFSET(CO31,0,1-COLUMN(CO31)), CO31<"")
then it doesn't work.

Anyone have any ideas? Thanks.