When people say there’s been an “𝑥 fold increase in such and such.” They mean such and such is 𝑥 times as big.
If you get something that actually folds like a sheet of paper, the amount of layers doubles each time. One fold = twice as many layers. Two folds = four times as many layers…
That’s only if you are folding the already folded paper. If you unfold after the first fold, then fold one of the halves in half, you’ll always end up with the number of folds plus one.
That still doesn’t match the intended meaning of the analogy though.