Duty Free/Yellow Number Plate Story! (Amman)

Yes, I know probably this has been discussed before here but I still need to confirm as no one has official news on it.

Apparently expats can only buy maximum 5 years old car, but for someone like me who can buy tax free/duty exempt car, does this rule apply too?

If it does than it doesnt make sense for people that are entitled to own a tax free car having one and it then becomes over 5 years old, effectively they wouldn't be able to sell them on, unless they pay the tax on it and sell it to a Jordanian. Which would cost more to the owner than it's worth. They will end up dumped in compounds and car parks?

Help please!