One thing we would note, however, is that it’s always best to work with a hosting provider that understands the importance of separating these different technologies from one another on the server. In other words, WordPress installations should not share space with Drupal installations. It creates for an insecure environment and can severely compromise your website’s performance.
It shouldn't come as any surprise that, like other web host providers, A2 Hosting's unlimited plans aren't actually unlimited. It expect you to use its service like "similarly situated customers." This is like being on a highway. If everyone is going a few miles above the speed limit, you're probably okay, but if you're barreling down the fast lane past everyone else, you're probably going to be asked to slow down.