Kaplan study text states that rolling budget are costlier than incremental budgets. Technically though, if a rolling budget is prepared and reassessed every 12months then the costs to prepare a rolling budget should be the same as costs to prepare an incremental budget which is also made on an annual basis. So am essentially struggling to understand why one would be more costlier(rolling budget) than the other(incremental budget).
Rolling budgets are generally prepared every months, whereas normal budgets are usually prepared only once a year.
I do suggest that you watch my free lectures on this. The lectures are a complete free course for Paper PM and cover everything needed to be able to pass the exam well.