Not even close.
The original source, as you can see here, was the first edition of the work you cited. And, as you can also see at the link, they did not use the "traditional Protestant way" (whatever that is), or any way you'd use in ordinary conversation. The second edition obvious uses the same definition (unless you've got evidence that 19 denominations, in the ordinary sense of the term, suddenly jumped to 30,000).
This is actually a side issue. By your answer, you proved that if you read it at all, you saw the number and ignored the context, trusting your own guesswork for the rest.
Sounds pretty clear to me.