Yes, this is incorrect. Also the next sentence is wrong: >You’ll often see statistical power conveyed as P90 or 90%. In other words, if there’s a 90% chance A

Yes, this is incorrect. Also the next sentence is wrong: >You’ll often see statistical power conveyed as P90 or 90%. In other words, if there’s a 90% chance A is better than B, there’s a 10% chance B is better than A and you’ll actually get worse results. Having a test w/ 90% power means that if A is truly better than B (for one sided) or A is truly different than B (two sided), then you'll detect it 90% of the time you run the test (on independent data).