I edit .L5K files by hand all of the time.
For instance, on the project that I'm working on now, I have a "Print_Pass" and a "Print_Fail" routines that only differ in that one has "Pass" as part of its tags, and the other "Fail".
I copied all of the rungs in "Print_Pass" (select all, right click, hit "Copy") and pasted them into NP++. From there it was a simple search and replace of the "Pass" occurrences with "Fail".
Next, I copied the modified text and pasted it into the "Fail" routine by adding an empty rung, double-clicking on it from outside of the rung (near the rung number), and making sure that it says "In Neutral Text" rather than "In ASCII Text" I paste those rungs (you can enter multiple rungs in at one time) that I modified in NP++. Then just click outside of the text edit box that you entered your rungs in and all of the rungs will appear.
Can you make a sample program with just one VFD in it and post it here for us? (preferably as a .L5K)