The monthly average spot price in Finland has not been that low during the winter in Finland in any of those years.
Also there is no way OL3 actually costs that much to build. Lets say it runs at 90% of max output on average it gets you ~14 000 000 MWh of electricity per year and with 60 year planned lifetime that comes to 840 000 000MWh of electricity produced.
With your numbers (the low end $0.13 per kWh) it would come to ~100 billion euros building costs which is roughly an order of magnitude more then reality (somewhere between 5.4 to 12 billion to be paid by TVO once all the lawsuits are settled)
At the end of the day with operational and decommissioning costs the overall lifetime costs will go up obviously but I doubt in the tune of over 1 billion per year to reach your estimate costs.
Also getting the profitability number of OL3 is really difficult due to TVO not actually selling any electricity directly to the public/pool but instead at cost to the investors of each reactor. Some of it going directly to Fortum or Helen who just sell it to whoever but some of it goes to the big paper companies who use it to run their factories.
TVO is a "mankala-periaate" company which I can't really find a good english explanation of but basically it is a company that sells all of its product to its owners at cost allowing multiple players in the field to share a single supplier while stills staying in control of the supply chain.