It is not a pre-requisite or an absolute. They are set up to be able to be modified according to need.Jeff, I think you misunderstand Iron Man's meaning.
He is saying that if HHQ-9 variants can be "dual packed" in the manner that he is proposing (which is indeed a just an idea) -- then it means his 052D loadout of having 72 HHQ-9 variants in only 36 cells will allow 28 cells to be used for other things.
Of course, the direct comparison to Burke or Tico in this case, is the prerequisite that a Burke or Tico must have 72 HHQ-9 equivalents in their cells -- aka SM-2 variants or SM-6s -- in 72 cells, because the Mk-41 VLS is not big enough to hypothetically dual pack SM-2 or SM-6 sized missiles.
In other words, what is being compared is not whatever mixed load of missiles that Burkes or Ticos can yield, but rather it is looking at the number of free VLS cells that Burkes or Ticos will have after 72 of their VLS cells are already used to fill up with SM-2s or SM-6s.
In the case of Burkes, it is 96 - 72 = 24 free cells
In the case of Tico, it is 122 - 72 = 50 free cells
In the case of 052D, it is 64 - (72/2) = 28 free cells
And add in the various non VLS cell missiles if one wishes.
This is all operating off the idea that the Chinese Navy's universal VLS could notionally dual pack HHQ-9 class missiles, and the idea that HHQ-9 class missiles are equivalent munitions to be compared with the likes of SM-2/SM-6 variants.
I do understood Iron Man's statement and implications, and they are strong implications...but when you start adding the ESSMs there with their specs, and then consider the modularity available to both the AEGIS vessels, you quickly (at least IMHO) can offset the overall implications.
Heck, if the pLAN can dual pack the HH-Q9s, as I say, it is a very strong implication/impact. I am not doubting that...but no one knows if it is even on the table or reality.
Anyhow, in either case, all four ships (Burke DDG, Tio CG, 052D and 055 are all modern, very capable ships.