Omicron does not grow “70 times faster” (bad math alert)

All we have so far is this press release: https://www.med.hku.hk/en/news/press/20211215-omicron-sars-cov-2-infection

If the numbers in the graph are total growth in 24 hours, then omicron=10000 & delta=~140.

Calculate log(10000)/log(10000/70) = 1.86

Ie, omicron grows 1.86 times as fast as delta, or 86% faster.

That's significant, but 1.86 is a whole lot smaller than 70.

(If the numbers in the graph are something else, then we actually can't tell what the ratio is.)