Data Loader Expression Input value

edited 12/09/19 in API & Developers

I am receiving a MS project file in an excel format and trying to load into a Project sheet in Smartsheet. I have a WBS column and from the WBS column by counting the dots I want to determine the level. The formula works fine in a sheet but when I write the formula on the expression input value as 

=LEN(WBS) - LEN(SUBSTITUTE(WBS), ".", "")) without the row reference I see "#UNPARSEABLE" in all the rows.


If I use =LEN(WBS1) - LEN(SUBSTITUTE(WBS1), ".", "")) then the number counter is not incremented by data loader and all rows is referenced to row1.


I am sure I am making a basic mistake any inputs will be helpful.