Wall_Application_Height input not accepting an expression output

Hello all,

I'm trying to set up a wall node that will automatically draw some walls along a series of user-defined lines, with a user defined height and width as well. However, it seems that getting user defined height and width is a bit iffy, at least in the version of GC I am using (CONNECT Update 3). 

The height and width of the wall are governed by Wall_Application_Height and Wall_Application_Width respectively, however when I plug in an expression with value "1235" for instance, the line does not draw but the entry for Wall_Application_Height changes to 'length(1234.859002225)', i.e. very nearly 1235 but not quite! 

The way I plug it in is draw a line from the value output (equivalent to typing expression1.Value in the Wall_Application_Height input). I have also tried just drawing a line from the expression itself, however this does not work.

I am stumped, can anyone help? 

Thanks, 

Walter