Procurement cost. And to be exact - powerplant still constitutes a significant part of the price(double digits).
But when we go to operation costs(and logistics load) - powerplant becomes of huge importance - the more active ship is, the costlier it gets.
That's assuming 052D can't do the same networking(or there is no 055 in TG).
Given that 052Ds are very recent ships, and their radar/cooperative engagement/battle management system development schedule proceeded at least partially in parallel with 055 - why such an assumption?
As per an old Arleigh Burke cost analysis I've read, fuel accounts for approximately 10% of the total lifetime cost.
It just doesn't seem that significant.