For a lesson in what happens when you continually delay ships, see Charles de Gaulle cost escalation, or more recently, the impact when MoD deferred MG for CVF back in 2003/4.
Fact of the matter is, the only thing you can do (without wholesale redundancies and consequent impact on ability to build in the first place) is slow the build down, which means throw less bods at it. Run-on costs for CVS are likely to eat up any savings in CVF build (which I thought was the whole point of combining EP and STP!) as Lusty & Ark (particularly the latter judging by her material state) will need another trip to Babcocks North.....