When and how does £265,000 of savings become £400,000 of savings?

What does one make of this, on the agenda of the Joint Overview and Scrutiny meeting to be held on Tuesday 9 February 2016 at 6 pm from the agenda papers and talking of the potential savings to be made on a new refuse and recycling contract:

“The recommended Lot being proposed in the report does give a saving to the Council in the order of £0.265m along with providing an enhanced recycling service. The draft budget however assumed a saving of £0.400m in line with our Transformation Strategy thereby giving us a shortfall of £0.135m in our budget proposals should members wish to adopt the recommended option. This issue is dealt with the Revenue and Capital Estimates Report 2016/17 contained on this agenda on the assumption that members adopt
the recommendation”

Click to access 090216-joint-overview-and-scrutiny-agenda-combined-public.pdf

It seems to say: This contract will save us £265,000 but the draft budget assumed that it would save us £400,000 and we have found a way to make it come to £400,000 …. by some sort of wizardly accounting?

How many committee members will take the time and trouble to look at the Revenue and Capital Estimates Report 2016/17 to see exactly how this wonderful accounting is dealt with and reassure themselves that 265 really does mean 400?