Upgrade instructions clarification needed

I am upgrading from mingus to strayhorn

The instructions say:
# Why delete? Because if the uploading (or upgrading through cPanel) does not correctly overwrite an existing file, you will get errors.
# Don’t delete wp-config.php or your wp-content folder though, as they tend to have important bits
# If the upgrade is minor (1.2.1 –→ 1.2.2 or 1.5-beta –→ 1.5), don’t delete your template files either:

<b>right here, does it mean do NOT delete these only if you are going from the above versions, but delete them if you are going from 1.2.2 to 1.5?</b>

* /wp-content/themes/ (for WP v1.5)
* index.php (you may have split it up into several parts; keep them all)
* wp-config.php (pay attention not to delete this file accidentally)
* wp-layout.css (or whatever you have chosen to call your customized style sheet)
* wp-comments.php and wp-comments-popup.php (if you have customized them; otherwise, you can safely delete them)

# If the upgrade is major, it is better to set the above files aside until the upgrade is completed. Note: In most cases, your old template files will work with the new WordPress version.