The Insanity of Plane Ticket Pricing

I've just discovered something that I truly can't believe while booking my final flight home from London to Fort Lauderdale (boohoo sniff tear). 

Paying in different currencies for Norwegian flights drastically changes the price of the ticket when converted back to dollars.

Exhibit 1: Paying in USD

Exhibit 2: Paying in GBP 

Based on today's visa exchange rate (1.53) this converts to $809.37. Already considerably cheaper than the USD ticket price. 

Exhibit 3: Paying in EUR 

Today's visa exchange rate for euros is 1.1 making this ticket $756.69. THIS TICKET IS $121.21 CHEAPER THAN THE DOLLAR PRICE. 

My credit card has no foreign fees on top of the visa rate - thanks Capital One - so I obviously chose to pay in euros. It's a great benefit.

Trying to diagnose this phenomenon I come up with two possible scenarios. 

1. Norwegian uses some historical exchange rate average to do the international ticket pricing. The dollar has gotten stronger recently so this could account for some of the difference. I still would expect their pricing algorithms to account for this better. I doubt they have considerable foreign currency costs. 
2. The pricing is discriminatory based on self-reported location. The option to pay in USD is only available if you say you are in the US. This would mean you (aka me) are probably not price sensitive when it comes to returning to my own country. Both options to pay in GBP or EUR are available if you select that you are in the UK. Okay, logical because of the EU, but still the pricing is different. Today's EUR - GBP rates makes the ticket in euro worth 495 GBP and the ticket in pounds cost 740 EUR. I guess if you choose to pay in euros you are less likely to live in either London or Fort Lauderdale, meaning you are on holiday and the most price sensitive of the three customer groups.

My mind is going all sorts of places. What if I had chosen to pay in yen? or a really obscure currency? Where are the travel blog posts about this? Am I the only one who was unaware? Wish I had thought to check this earlier because I'm positive I would have saved some money.  Hopefully you, friend, will think to try this next time you book international flights.