If the subsequent Hubbles cost as much as the first one was supposed to cost: about 10 Hubbles

If the subsequent Hubbles cost as much as the first one actually cost: about 0.5 Hubbles

It's not totally on apples to apples comparison. There would probably be some cost reductions if you made ten hubbles. On the other hand, some of the servicing missions upgrade or even added instruments, so I suppose you'd need to take that into account