PBGC uses the plan termination date when calculating the present value of pension benefits owed to participants in a PBGC - trusteed single - employer plan. (pbgc.gov)
For each respondent, I calculate the present discounted value of their pension benefit at a given age of separation from teaching based on the pension plan description in Costrell and Podgursky (particularly Table 2, which shows the replacement factor for each combination of years of service and age). (educationnext.org)
Some suggest the realised value of your pension benefits (i.e. accumulated payouts) is checked against the LTA, so you pay the extra tax on any and all income drawn after exceeding the limit. (money.stackexchange.com)