Orders of magnitude require at least 3 data points, and you have only 2.

I know this is getting off-topic, but as a non-native speaker, I'm interested in hearing how a third data point would be needed to judge whether things differ "by an order of magnitude". I was under the impression that "an order of magnitude" meant "one more digit", meaning very roughly a 10x difference. "a >= 10*b" can be determined without the need of a third data point. Is there some other meaning to the phrase I haven't come across?

Not the original poster, but you have it more or less correct. An order of magnitude is 10X. Orders of magnitude just refers to “at least 100X.” Colloquially, orders of magnitude just means “significantly more/less.”