Avios cost for 1 person vs 2 people doesn't add up
Hi, I'm sure this has been asked 100+++ time, so apologies for that.
I think I'm going mad.
I'm looking to use my BA companion voucher, but nothing is adding up for me in terms of Avios points.
Looking at Belfast to London return - Business Class - in a couple of weeks.
When I search the Reward Flight Finder for 1 person, the cost is 15,000 + £25.
But, when I use the same Reward Flight Finder to do the same search for 2 people it's 60,000 + £50.
I've definitely done it all correctly. Multiple times. Didn't go near the 'book with voucher' page. I just don't understand the increase in Avios cost. (x4 instead of x2).
So, I had thought I would get 2 of us to London & back for 15,000 but instead it's costing 30,000, (which adds up correctly to the 2-people search), but it feels like I'm getting completely shafted as I'd spend 30,000 if I just booked 2 separate individual flights using the Reward Flight Finder for 1 person at a time and didn't use the voucher at all. So, I'm really not getting the 2 for 1 deal here.
Is something wrong with the BA site search sometimes, or am I missing something obvious??
Thank you in advance!