Could I pay back now, and wait until I am 69 or 70 to refile?
I'm pretty sure you can, although I don't know why you would want to (other than to lower your current AGI). Why not just wait and repay and restart at 69 or 70? Folks under full retirement age who go back to work, repay in order to restart when they finally retire, so as not to lose benefits while they are working. I believe this was the genesis for the strategy in the first place.
I keep wondering about the surviving widow who switches to the spousal SS. Can the widow do a "buy back" of the deceased' years? A person could be "planning" a buy back at 70 but drop dead without warning before the planned buy back.
This is a good question. I asked it of OAG, and his feeling was that since a spouse is an "interested party", he/she could probably file for repay and restart of the deceased spouse's SS, but he wasn't 100% sure.
A couple of things to keep in mind:
If your AGI exceeds about 85K (for a single filer), you are assessed with a substantially increased Medicare Part B premium. Also, I believe Obama wants to reduce the "doughnut" in Medicare Part D with a 50% subsidy for brand-name drugs in the "doughnut", but this subsidy will not include those who pay the extra Part B premium. IMO, SS will probably go down this same road with additional means-testing, perhaps by raising the maximum taxable portion from the current 85% to 100%. For couples filing jointly, the threshold is 170K, but a surviving spouse will be exposed to the lower 85K amount. For someone near the threshold whose entire income (other than SS) is portfolio income, there is flexibility to keep the AGI below these limits, but it requires monitoring/planning. Additionally, at age 70.5, those with regular IRA's (as opposed to Roth's) will face required minimum distributions, which will add to the AGI. Of course, all of the above will affect the "delay SS to age 70 decision" as well.