Here are my thoughts…
That number is flowing into the balance history tab and since that tab is a moving target (rows are always being pushed down to make room for the new feed data coming in every day), I do not think you can automate it with a formula. However, you can change the amounts manually, after the fact. The number probably comes in daily so that would be a pain. I guess you could manually update 30 numbers once a month but if you look at your balances tab regularly, then that number would always be off. Don’t like what you are hearing so far? Read on.
You could unlink that account from Tiller. You could do what you want with the past data. Going forward, you can create a manual account in the balance history tab. You can add manual entries as often as you want. It sounds like annually would be good enough for you. Make a manual entry today and put a number in. Tiller will continue to use that number into the future until it sees a future date with a different number. That would be the manual entry you make one year later. Create a new tab called wife’s school pension. Use that tab to set up a calculation methodology. You could get more accurate than valuex12x25. (What does GAAP say? Probably an unfair question. But, I guess you could be doing a compilation.) I am sure the website has a future value calculator. Enter your inputs. You could do a little calculation every year as your inputs would likely change every year. That would allow you to forget about it and just touch it once a year. That tab would provide your audit trail. Everything would be documented on that one tab. Let’s say in five years you come up with a better calculation methodology. You could go back and change prior years and then just update those five prior annual numbers in Tiller. This would provide consistency when using Tiller to compare net worth, etc. from year to year.
I basically do this for an annuity that my mom has. I want to know what that value is as it decreases every month. It has value. It can be sold. There are people all over the place that will buy income steams.
Please let me know what you think.