You do notice the two deck protrusions from both the fore and aft superstructures into the amidship section on the 054B, right?
View attachment 117905
The 054A only has one deck protrusion from the aft superstructure into the amidship section.
And even if/when the CGI 054B differs from the real-life 054B in terms of available spacings in the amidship section - That difference isn't big enough to justify 16 YJ-12 AShM canisters in that section anyhow.
Besides, I made the aforementioned observations based on
both the CGI and the photographs at Hudong-Zhonghua, not just the CGI.