I have found that most addon instructions use the following:
REPLACE, EDIT ADD BELOW, ADD ABOVE, CHANGE TO, ETC.
When you use a variety of the above in your addon instructions there is an increased chance that people will encounter errors (when copy/paste).
Here's your typical addon instructions:
ADD BELOW
ADD BELOW
ADD BELOW
ADD BELOW
ADD ABOVE
REPLACE
ADD ABOVE
ADD BELOW
VS.
REPLACE
REPLACE
REPLACE
REPLACE
REPLACE
REPLACE
REPLACE
REPLACE
Using REPLACE does the same job but it decreases errors.
LOL ... it's not full-proof but it has worked for me.