On the lines you say work, you’re assigning lxCt a text value of “Wk36”, not the value from a field named Wk36. Then you’re activating the lxCt field. There’s nothing similar in the lines you say don’t work.
In the first two to those, you’re using what are known as implicit assignments. They don’t work in Pan X. There’s good explanation of this by Jim Rea at Converting old procedures to Pano X - #4 by admin
The third assigns a numeric value to the current field. It would have to be a numeric field in order to accept it, but do you know you have the correct field activated?
The fourth is assigning the value of the current field plus five to a field named Wk34. Both Wk34 and the current field need to be numeric.
If they’re not working, how so? They run and nothing at all happens? If there are error messages, you should share them because they offer significant clues.