How does a professional editor scale their editing rates by word count?

I've been thinking about this a lot as a college student with big dreams of becoming a professional editor. I can already edit well. But I'm wondering how professional editors get paid more if the work is basically the same across the board. By which I mean the quality of work is the same no matter the word count. If I'm doing the same quality of edits, scale matters very little.<br><br>So if I edit at the rate of 1/5 of what I edit now, but charge 5 times as much, I'd still be making the same rate (so if I edit 1,000 words in an hour now and charge $25, and then I edit 200 words in an hour but charge $125, I would still be making $25 per hour at scale). I don't yet know what rate editors are paid by a firm, but I'd imagine they're more than $25 per hour, which means they can edit more words in an hour and get paid more. Am I on the right track here?