I assume the cost is quoted from 15 hours? There is no such thing as a "JAA" 15 hour requirement. It depends on your experience. My conversion was done in 3 hours training plus 1.5 hour checkride. Rented a Seneca and went for a ride. Simple. Got IR, ME Comm in one shot. If you are coming from the US then you probably got a fair amount of ME time. Don't let them bamboozle you into thinking that you need to buy 15 hours. Trust me, the person typing up your license could care less.