Here, before the usual suspects read the headline and start on their usual half-baked yelling of "just goes to show DLA must be cut".
"When claimants reach state pension age, disability living allowance and attendance allowance are combined into a single weekly payment with state pension and pension credit."
The DWP got its sums wrong and paid the wrong combined amount to many pensioners, going back at least 5 years. It was told to fix this in 2007 but carried on with the same mistake (though not necessarily the same recipients).
This £16 million error will of course be included in any DWP figures which state, "£XXX lost in DLA fraud or error, " as such errors always are.
As you were.