I just watched a YouTube video of Buddy Velasco demonstrating how to make SMBC, and he said to cook the sugar/egg mixture to 220.  Not only did he say it, but when he stuck his thermometer in a graphic "220 F" popped on the screen, so I don't believe it was a mistake.   

Is that reasonable?  I thought customary was between 115-160 (notwithstanding debate about salmonella risk).  I've never gone past 160 myself.    

Not sure it will be allowed, but here is the link to the video:  

I agree, it sounds awfully hot. That's almost the temperature for the sugar syrup in IMBC.  I too heat my whites and sugar to between 150 and 160F for SMBC.   In fact, since water boils at 212F, it seems to me it would be impossible to get the eggs to 220F in a double boiler since it is heated by the steam.  Unless under pressure, the steam could not be more than 212F.  Probably a mistake.  

Even though he annoys me to pieces, I have to say he knows his stuff. I am inclined to believe he said what he meant to. The only way to know for sure would be to try it.

It’s an error. If you go read the recipe on his site it says 160. 

http://www.cakebossbaking.com/recipes/swiss-meringue-buttercream/