Not sure I believe your 'pensions calculator' example.
My expert on this is..... me! Do the research, then the sums, it's not hard.
Ok, here are the two options (I will ignore the effect of inflation to make the sums easier.
OPTION ONE - Serve to 55.
Easy, retire on full (100%) pension. One tax free lump sum of 3 x pension.
Let us use an example of a pension of £32,000. So, we have at 55 a lump sum of £96,000 and an annual pension of £32,000
OPTION TWO - SERVE TO 54.5.
Assuming pension earned is still £32,000. Retire on 75% of pension, £24,000. Tax free lump sum of £96,000 still.
Now between 54.5 and 65 the pension is only £24,000, compared to £32,000 in option one - a loss of 10.5 x £8,000 = £84,000. HOWEVER, and this is the point, under option one that extra £84,000 earned would have been taxed, so it would have only been say £63,000 in your pocket. Which means that under option 2 you are so far down £63,000. But at 65 you get another tax free lump sum of £96,000 - meaning YOU ARE £33,000 UP OVERALL!
Whichever way you look at it you make more money under option 2, in terms of about 100-120% of your pension.
The decision as to which option to take will depend on such factors as:
Do you expect to live to 65?
Do you need to maximise your income at 55, or are you planning a second career and can afford to wait until 65 for maximum pension income?
etc, etc.....