If the normal retirement age of the scheme is 65 and you retire at 60, generally (depending on the scheme) the pension is reduced in 2 ways.
1) 5 years less service to count
2) the actuarial reduction on the reduced pension
If you reduce the normal retirement age to 60, you get rid of 2), therefore don't have a "double whammee"
I am not suggesting you can get rid of 1) but getting rid of 2) can make a big impact.