Oh sorry I understand (now) after re-reading your point.
Earlier today I read a different version of this story - which focused on the dividing line between China and Taiwan.
The gist of that story was, the last time the PRC violated the mid-point of the Taiwan Strait was in 1999. The story mentioned the US plane was already out of the area, by the time the ChiCom jets crossed into Taiwan airspace.
The description mentioned something to the effect “obviously at a different altitude” than the American jet.
So while China may have such capability, they did not use it this day. I’d hope our own people presume they can, just to be prudent.
Apparently the SU-27s have a ceiling of 62,000 feet.
Pretty impressive but they would have precious little maneuvering capability at that altitude