And if you already have 7+ Brigade locations, that is enough coverage already and you don't need additional launch locations.
So if you're going to vastly increase the number of launchers, does it make sense to create additional brigades next to the existing ones, or just make the brigades bigger?
When coordinating a missile launch to overwhelm middle defence, it's easier to do this with 1 brigade with 36 launchers than 2 brigades with 16 launchers each.
EDIT. Wasn't it previously 5 brigades with 16 missiles each?
The DF-26 launchers and reload vehicles are extremely heavy and cumbersome. Their mobility requires extensive support from engineering units, along with accompanying CBRN troops and technical support detachments. If additional launchers were added to a single brigade, the brigade’s overall personnel would expand to an unacceptable level, creating a major burden on command, control, and administration.
Therefore, I believe the number of launchers will remain at 16 per brigade. If additional combat capability is required, new brigades would be formed instead.
In addition, “Nugget” has mentioned that the DF-21 has been rapidly retired over the past few years, with the original units re-equipped with the DF-26. The reason is that, after PLA assessments, the U.S. Navy’s Standard Missile-3 Block IIB was expected to have a relatively high probability of intercepting the DF-21D.