Yes the line numbers are assigned so you can edit at command mode if needed when running in text mode. Mind you with PxPlus 2023 due in May you should be able to run EZWeb on a Linux/MacOS/AIX box then use ED+ to edit your programs graphically from any browser.
When looking for the closing bracket the system has to scan ahead through the code, this is due to the interpretative nature of the language and that you can alter code at run time. Given this, from a performance perspective it is better to keep the directives on one line as scanning will be faster.
Also, as mentioned earlier, I generally prefer moving multiple lines to smaller subroutines. A GOSUB takes very little time and will often run faster than scanning looking for brackets. I also find it has the advantage that if I need to insert additional lines into an IF condition having them in a subroutine makes that easier especially when they are sub-ordinate IF directives. I find it also helpful if the subroutine name provides a 'clue' as to what the logic is doing.
IF QtyOnHand <= 0
I have seen far too many programs not work because someone inserted or changed a few lines of code in between curly brackets that they didn't realize were present. By avoiding curly brackets and using *IT or ED+ to format your code I find it makes it more readable and supportable. I almost never use curly brackets (but maybe I'm just a bit weird in that respect).