I have treaded lightly so far because I don't 100% understand exactly what your plan is and I'm about 99% certain that you don't actually correctly understand what the tax laws and rules are about both 72(t) and Roth conversion pipelines. I suspect that trying to clarify either of these topics might be a lengthy and difficult process for which I am not sure I have the appetite.
But I'd like to try on a limited basis to keep going on this topic because I do know some things about this subject. (Or at least I'm fairly certain that I do. But to you, of course, I am just SGOTI.)
So first of all, what it sounds like your potential plan is to me: Start a 72(t) series of substantially equal periodic payments from your Roth IRA by notifying your custodian. After a few years, there may be some reason you wish to stop the 72(t) payments. You do so by notifying your custodian. You then go amend your tax returns for those years, wishing to restate those payments as Roth withdrawals against your "5 year conversion basis". By this latter term I think you must mean the sum of your contributions plus any conversions that are older than 5 tax years at the time the withdrawals were originally made.
So let me state and restate some of my concerns that I think you might be wise to try to clarify:
1. First, your original post seems to suggest that you think that the minimum time requirement for a 72(t) SEPP plan is 5 years when you write "lower time commitment that the 5 years". The minimum time requirement for a 72(t) SEPP plan is 5 years or until age 59.5, whichever is *longer*. So if you start this plan at age 45, the minimum time would be 14 or 15 years, not 5. This is not directly applicable to your plan, since you think you have a way to break the plan early. But if you are wrong, it does point out that the downside risk is potentially longer/larger than you think it is, so I wanted to restate it.
2. As I think you know, you can only amend tax returns going back 3 tax years. So one problem with your plan is if you start a 72(t) plan and decide to end it in year 4, you would not be able to amend that first tax year, which would logically therefore still include a 72(t) withdrawal. The IRS could then see that you had broken a 72(t) in year 2 and would assess taxes and penalties accordingly.
3. You believe that 72(t) withdrawals from a Roth are exempt from ordinary income taxes. They are not and I believe you are flat-out wrong on this, but feel free to search the IRS site and/or find a reputable expert to ask. This is a little understood point about 72(t), but it is true and is one of the main reasons why SEPPs are practically never done on Roth IRAs.
As one quick citation, please see the first page of this Vanguard document (
https://personal.vanguard.com/pdf/s164.pdf) which states "Ordinary income tax Yes.**" This is also a short and reasonably understandable primer on SEPPs from a reputable source.
So your plan doesn't make sense to me from a practical point of view: You'd be paying ordinary income tax on your withdrawals from your Roth under a plan which avoids the 10% penalty yet requires you to continue making those withdrawals for possibly longer than you want in order to preserve the option to retroactively amend your taxes (i.e., do extra work) to a situation where, had you just done regular withdrawals in the first place (as part of a Roth pipeline), you would have owed neither ordinary income tax nor the 10% penalty and would not have been obligated to continue the withdrawals in the first place.
4. Setting all that aside, part of your plan seems to hinge on amending your taxes to retroactively change your withdrawal from a 72(t) to a regular withdrawal. I see a problem here. When you make the withdrawal, your custodian has to report a code to the IRS on the 1099-R so that the IRS knows what the proper taxation of that withdrawal should be. Presumably under your plan, when you make your withdrawals initially, your custodian will report them to the IRS with a SEPP withdrawal code. Later if you chose to change your plans and amend your taxes, you're wanting to just tell the IRS that the withdrawal was not part of an SEPP. But the IRS has a 1099-R that says that it was. Either you will have to have a discrepancy between your amended tax return (which says that the payment was not part of a SEPP) and the original 1099-R (which says that it was part of an SEPP), OR you will have to get your IRA custodian to issue a new 1099-R to the IRS with a different code. In the former case, I think this subjects you to audit risk and retroactive penalties by the IRS. In the latter case, I think your IRA custodian will say that they can't and won't do that. How do you plan to address this difficulty?
...
To answer your question here: "Why would the Roth be "converted" back to a TIRA?" I assume you are referring to what I wrote: "I don't think there is any way to retroactively convert 72(t) withdrawals to Roth contribution/conversion withdrawals." My sentence is (1) a more compact statement of item 4 above, and (2) was referring to the fact that you were wanting to conditionally change your withdrawals to being from "5 year conversion basis", which to me can only mean - based on how the IRS treats the ordering of Roth IRA withdrawals - from your Roth IRA contributions then from any conversions you have made to your Roth IRA from your traditional IRA.
5. You seem to want flexibility. I think you understand this, but SEPPs, generally once you choose a plan, the amounts are fixed down to the penny. See "An important note" towards the beginning of this Forbes article:
https://www.forbes.com/sites/advisor/2012/02/13/the-72t-early-distribution-from-your-ira/#1d8173aa2068It sounds to me like you've drawn some conclusions based on incorrect information you've heard along with your common sense and logic. Unfortunately, common sense, logic, and how we think things ought to work don't always apply to taxes.
Good luck!