Listing Edit, Renew, Upgrade

Hi, just wanted to check about these 3 options in author action, and what is the difference in these:
1. I suppose Edit shows on all listings, upgrade appears if current package has setting “has upgrades”, regardless of listing status , and Renew appears only on lisitngs with status expired – is that right?
2. The package choices available – Edit shows all packages with current one selected, Upgrade will show other packages than current, renew shows all available with current one selected
3. URL shows task = renew or task = upgrade – but is there any difference in the behaviour?
4. If a different package is selected using either edit, upgrade or renew then is there any difference in the checkout > subscription process between these author options, or are they the same?

thanks, Vivek