The direct announcement (https://www.oxfordpv.com/news/20-more-powerful-tandem-solar-...) seems to have more nuanced wording:

> The 72-cell panels, comprised of Oxford PV’s proprietary perovskite-on-silicon solar cells, can produce up to 20% more energy than a standard silicon panel.

I think "standard silicon panel" and "up to" is doing a lot of heavy lifting. They might also be using the lab number (26.9%) rather than the 24.5% number. But then it says:

> The first Oxford PV panels available on the market have a 24.5% module efficiency, offering performance significantly above traditional silicon technology.

AFAICT, the real news isn't a massive efficiency win, but that these are actually going into production.