Latest news: Boeing announced today that their offer includes option to buy Loyal Wingman drones on top of the 64 Super hornets/Growlers, all within the budget.
So as LM announced earlier that their offer is up to 64 F35's within 10bn€ (in essence offering F35's on the same price range with 4th gen competitors), Boeing is matching the raise. My uneducated guess is that Boeing is trying to avoid the Swiss decision of buying F35's at all costs.
This is evolving to be rather interesting. The winner is to be announced later this year.