With SSL Labs the only difference between A and A+ is if your sending the HSTS header with an age of at least 6 months.
For renewal it depends on the method used to originally obtain the cert. As the documentation states the 1st example only work if you used
webroot and the
nginx plugin require nginx to be running to complete the challenge. In this case you should use
"service nginx reload" with
--renew-hook. The 2nd example would make no difference on it's own and would be used as part of a shell script.