Yep, you're right. I was thinking about compressor maps and the surge line is on the left, so I was thinking it meant it was not flowing enough air. Surge is when there is too much pressure on the output of the turbo, forcing air back into it. My bad for mis-thinking I'll go back and edit my post.

So surge isn't the right word, but is the concept correct? In that, there might not be enough air flowing into the supercharger?