I have just noticed something really weird.
If you are logged onto Fiverr and "pretend" to order a translation or proofreading gig from someone, the multiple option totally disappears and you cannot order mutiples of the same gig AT ALL.
If however, you try and order the same gig by being logged out of the website as a typical client would, then the multiple option reappears.
It definitely is a problem and Fiverr MUST address this without delay.