For things like production counts, it is simply difficult, if not impossible to track those if the PLA actively wants to keep production numbers a secret.
It's rather easy to just prohibit and warn of releasing images of factory airfields and aircraft serial numbers in the day to day -- because that is really the only way for us to track them. Nor do we have access to round the clock satellites of airfields and factories that nation states do.
Whether it's J-16s, J-15Ts, J-20s, or J-35/As, our ability to track actual numbers is virtually non-existent.
Even for J-15T, a few years back in 2021 (when the existence of J-15T then known as J-15B) was confirmed, we were able to at least have an estimate for when the PLAN may receive them, from an article I wrote at the time:
"If the J-15B emerges within the next year or so as currently expected, it may be ready for handover to the PLAN before 2025."
And I was pretty much on the money in terms of timeline, because it was viable to estimate the developmental time needed for an aircraft like J-15T to go through the EMD process given SAC's existing Flanker family experience -- but in terms of production scale, that is basically impossible to determine by anyone, because without knowing the year to year order/breakdown of SAC Flankers (how many J-16s will be built versus how many J-15Ts, for example), we exist in a state where they can simply jumpscare us with a brigade or two worth of new aircraft in the span of a year and a half.
However by virtue of needing to be evidence based and sensible, we cannot simply assume to know what an annual production breakdown is, without credible rumours to give us a foundation to work with.
(076 starting construction was actually somewhat expected, and anticipated because we had some rather clear rumours as early as 2020 about what it would look like.)
