Actually, I think that the page that is asking for prior-year distributions is asking for the value for the purpose of determining the amount of the penalty on Form 5329 for an excess traditional IRA contribution, should it be needed, not for anything having to do with Form 8606. (TurboTax asks for the year-end value separately for these two different reasons.) Still, prior-year distributions are irrelevant to determining your year-end value for the purpose of an excess contribution penalty.
