I suspect the tip petals handle deflection but the base petals handle throat area for the divergent section.
These last few images nicely show how the TVC construction works. The outer petals which are not wholly movable in all directions (except for their ends) and which hold in place the inner petals which are the ones that do the moves. I'd say the outer part of the structure is different even from the MATV, even though the inner petal movements might be the same. (green lines are inner petals, or the inner nozzle, red lines are outer petals, which only contract and expand, but can do so unevenly)