On my way to search for difference between Park Domain Versus Addon Domain, I found an interesting argument on SiteGround forum.
Some of the points being discussed are:-
“The purpose of the Parked domain Cpanel function is to allow the customer to have more than one domain name opening his/her website. This means that Parked Domains are not intende to be used to serve different content from the primary domain.
The Addon domain is the function that allows you to have more than one website hosted on one account.
Using Parked domains as Addon domains with the help of htaccess is not allowed on our servers.”
They also mentioned on using .htaccess to turn park domain into addon domain, which I am VERY interested now bacause I have used up all my 9 addon domains, and with unlimited park domain, I think this trick will help alot.