How much is 650 when you need 2 to tap on an easiest target or 4 on a high performance target? A year worth of production is only enough to deal with one air raid, of which 75% of the targets will get through. Not to mention missiles that will be destroyed in storage, in transit, or with the launchers that are going to get hit.
It is more than what you were trying to mislead people with, the system is in high demand in the world, very popular, so other countries are starting to be licensed to manufacture it and components.