Analysis by the ADC of the bids for unitary status submitted to the Local Government Commission suggests that one-off transitional costs are also relatively small. An internal briefing paper claims that unitary status should be achieved without 'significant effects' on local tax payers.
But figures from 11 districts quoted in the briefing show significant differences. The total estimated increase in expenditure of these districts comes to £70 million compared with county estimates of savings at £50m - a difference of 39%.
The gap on estimated transitional costs is even greater at 124% with eight of the counties affected putting start-up costs at £34m compared with the £15m district estimate.
Other figures match more closely, with counties commonly predicting cost reductions of around £1m less than districts' estimated increase in expenditure.
Of the 21 councils up for review only 16 bids for unitary status were submitted early this month. The figures contained in these bids will be subject to scrutiny by the Audit Commission in an attempt to overcome differences before the Local Government Commission makes its recommendations.
ADC policy officer Crispin Moor said that in absolute terms the gaps were not that great.
'The Audit Commission should be able to identify why there are gaps and apply some sense to bridge them,' he said. Mr Moor added that at the end of the day the exercise would end up being cost neutral.
'These figures clearly demonstrate that costs remain a key issue locally,' said Association of County Councils finance under- secretary Mike Grealy.