One of the bright sides of Nokia joining the Windows Phone entourage was the fact that Microsoft agreed to shell over a quarter of a billion dollars per quarter. This effectively had given Nokia an edge over all other WP OEMs seeing how for the past year they were operating at an almost no cost expense to use Windows Phone; or in fact were making money by using the platform.
However with the increase in Lumia sales (4.4 Million) the tides have turned, seeing that the amount of software royalties Nokia has to pay has for the first time exceeded the 250 Million quarterly payout by Microsoft; but this is a small price to pay for success; one that Nokia can now afford seeing how they’re officially in the black again.
Also it’s likely that Nokia will be receiving a bit more payout in the future due to licensing Nokia Drive to other WP8 OEMs; which should once again give them an advantage over other OEMs.
Of course this could explain why Nokia are interested in continuing to produce WP 7.X devices (such as the 505 and the 510 etc.) seeing how the licensing fees are sure to be less than those for WP8.