Reward vouchers and short of points

Can someone help me clarify my understanding of reward vouchers please in my circumstance?
- Gold with 3 unused reward vouchers, so 150k points each
- Wanting to purchase 4 upper seats requiring 770k points
- 192,500 points per seat I assume?
- As I understand it, I have to purchase a seat with points of miles and can then use 1 voucher. So I would have to purchase 2 seats with points and use 2 vouchers?
- 2 seats would be 385,000 points, meaning I'm 50,000 points short
- I think I should be able to purchase the extra 50,000 points for £750?

So by my calcs, my total would be:
- All my 335,000 points
- £750 to purchase the extra 50,000 points
- 2 reward vouchers
- Taxes and fees for upper seats circa £4k

An agent I spoke to just said I needed close to 500k points and 2 vouchers which I don't understand and half the systems weren't working anyway so I gave up.

Hi,

You have: 335,000 + 150,000 + 150,000 =635,000

You need: 770,000

You need to purchase 135,000 points

Mike

Damn, I've neglected the 42,500 points I'm short per voucher.

Thanks for clarifying