This value was calculated, I have been told, based on the amount necessary to give me a deferred pension of 2/3 of my salary
I would be very surprised if this was the case unless you had over 40 years service with the organisation. I would think that the transfer value is calculate based on you receiving a pension at age 65 based on the number of years already worked.
No of years with organisation 25
Salary 40,000
State pension say 10,000 for the sake of this illustration.
Pensionable salary 33,750 (40,000 - (10,000 * 25/40))
Pension 33,750 *25/60 = 14,063
Is this guaranteed. If so why are they closing the pension scheme?
If not does it become part of your defined contributions. You may end up with a smaller pension in relation to your 25 years with the organisation. The value above can fall as well as rise? Check this out?
Have you your previous pension statements. These are issued every year (legal requirement). Compare the current statement with previous one.
There are calculated using acturial methods