The Movable Retirement Age

I have been pondering if the age of retirement should be raised as the current Government seem to have a penchant for, or lowered.
By raising it from 65 to 67 as the Government did recently, the state doesn't pay out until two years later and to be bluntly honest, there are less 67 year olds than there are 65 year olds so the amount they have to pay out is less but that means people stay in employment for a further two years meaning less jobs available.
On the flip side, if the retirement age was lowered by two years, the Government would have to pay out state pension earlier and there are a lot more 63 years olds than 65 year olds but there would be more jobs available so they would save in having to pay out unemployment benefit.
Currently the cost to the Government for state pensions is £164 billion while the bill for unemployment benefits is £55 billion so it suits the Government to pay out unemployment benefit and keep the pensioners in work for a further two years and have less of them reaching 67. 
The contentious point is that through National Insurance contributions, the pensioners have paid in for their state pensions so it seems a bit cruel to make them wait a further two years to receive what they have paid for and it only needs some bright spark to realise hang on, we can make further savings if we move it to age 69 as there are a lot less 69 years old still knocking about.