Hi Dhruv, your problem is more so related to how the windows shell scripting works, as opposed to tabcmd. It seems that multiple delimiters right next to each other are treated as one. Here's an example.
There are a few ways to fix:
1. When Filter3 is ALL, is there a way to insert a blank in to the line?
2. Do slightly more scripting. See this as an example. null - Reading empty values in "for" command in a windows batch file - Stack Overflow