How sure of this are we ? If i remember the photo was captioned saying it was the first test flight of the new year.
I believe that image of 07156 didn't have that caption? I remember it was associated with the new year but didn't claim to be the first flight of the year (but perhaps my memory is wrong).
Edit : ah yes, I remember now it was for the new year of the Gregorian calendar, where they had that picture associated. There was some different news around Chinese new years.
Of course keep in mind it likely wasn't the first flight of that particular airframe CB07156 given it is already painted (new production J-20s tend to fly in primer first), and the picture may not necessarily even be related to the statement itself.
Maybe the answer is a lot simpler then we think and 155 was the tally at the end of 2022. That number would not have seen low if you made the prediction at the start of 2022 (maybe even on the high side). It only seems low now because of our erroneous earlier prediction after Zuhai when we thought they had 208+ or whatever it was.
Building on this how long does flight testing typically last ? They could potentially have a lot more airframes built then have passed flight tests.
It would be unprecedented for them to release an image of the actual "most recent" aircraft produced at a time when that was accurate. That is to say, at the time that the image of CB07156 was released, it serves as a foundational minimum for us, but is very unlikely to be a maximum.
And in addition to above, even if we assume that CB07156 did make CACs first flight of the new year, it doesn't mean it was CB07156's maiden flight (given it was already painted), and doesn't mean that it represents the maximum of the produced aircraft either. It could very well just be the aircraft which happened to fly first in the new year.
