I think this is still one of the strips where he was forced to have the top line of the strip as something that could be cut off and yeeted by newspapers that wanted a smaller comics section? He wrote a bit about how he hated it, forced him to waste space on a throw-away joke, couldn’t compose things just the way he wanted, and he was always experimenting with ways to disguise it.

Shows his skill as an artist that it’s so hard to tell, of course - like you say, so smooth.