Let me try again, I think I misunderstood your question. No, you don't need multiple IRA accounts.
There are two different 5 year clocks. The "earnings" clock, as you refer to it, says that withdrawal of earnings are taxable if the account has been open less than 5 years, even if you are over age 59-1/2. There is also a "conversion" clock that means that if you make a traditional to Roth conversion, this is subject to a 10% penalty for early withdrawal if the conversion is less than 5 years old AND you are under age 59-1/2. Each conversion has its own 5 year conversion clock, but the "earnings" clock only has to be satisfied once. As long as it has been at least 5 years since opening ANY Roth IRA, all your Roth IRA accounts are deemed to have satisfied the earnings clock.
Plus, as stated, the conversion clock doesn't apply after you are over age 59-1/2.
All Roth withdrawals are treated as though you withdraw contributions first, conversions second, and earnings last. You don't track individual dollars, and you don't track the balances of separate Roth accounts separately (if you had more than one account). All Roth IRAs are aggregated for this purpose. You simply need to know the amount of your contributions and the amounts and dates of your conversions.
The bottom line really, is you can ignore all of this. You are over age 59-1/2, and your Roth account was opened more than 5 years ago. From now on, all your withdrawals are tax-free, no matter if they are conversions, contributions or earnings, and no matter how long ago a conversion was.
