[Notjohn]

Actually, I think in standard book-making, all ellipses are three characters. When a fourth is added, then it is a full stop (period) and not technically part of the ellipsis. (It could be a question mark, exclamation mark, or even a comma or semi-colon or colon instead.)

I was assuming that three or even four dots without a space between would be regarded as a single word by most or all e-book platforms. Am I wrong about that?

The only case I can think of where a four-dot ellipsis would change under my e-book formula is where the omission comes at the beginning of the following sentence. In a printed book, I would go dot/space/dot/space/dot/space/dot/space, but in an e-book I would go dot/space/dot/dot/dot/space.