I believe I know why I am getting the 00.00.00. This is not generating in the cells Brian helped me with. A new column with zeros is being created in my crosstab because of the design of the Excel spreadsheet. There is a calculated "total" that they inserted in a separate row beneath all the "time in" dates we are using in the crosstab.
This "total", unfortunately, does not have the "time in" date associated with it in the same row, so the zeros are showing up.
I still want this "total" to show up in my crosstab. I just want to suppress all the zeros that are now being created and prefer to have blanks.