"What part do you object to? The Anthony or the Edward?"

Had Thor been asked to call Tony by his given name a few years ago, he almost certainly would have called him Anthony. A few years in space after the Battle of Sokovia had softened him in a way that nothing else had in the over millennia before it. Those visits with Tony probably helped, too; he slowly developed a sense of humor after hours of Tony Stark-esque quips. Everything was not nearly as formal as it had been.

So it was not Anthony, but Tony.