First, I want to own my mistake in the original post: I was completely wrong to include that decree clause about "gains and losses." That language strictly applied to a separate contract (Contract #1) and I should never have muddied the waters by including it here. You were entirely right to point out how confusing that was. For Contract #2 (the PA University 403b), the Date of Marriage baseline is undisputed and fully on the record.
With that cleared up, I want to thank you for this excellent insight. Your explanation regarding the investment provider's algorithms and their reluctance to assume liability for historical calculations makes perfect sense. It validates my suspicion that TIAA's rejection of the subtraction wording is a purely administrative and liability-avoidance measure, rather than a flaw in the legal tracing method itself.
Knowing that this is a recognized industry hurdle reinforces my strategy to bypass their system entirely. I will be proceeding with an Agreed Fixed-Dollar DRO, effectively doing the math for them to avoid further delays. I greatly appreciate you taking the time to share your expertise on how these providers operate behind the scenes.
