Yes, you can call this 'data mining' if you want. I've considered that.
I'm not sure it is 'data mining' any more than a regular run though. It's all the data we got, and we can only get so much info out of it. You can think of the ratcheting like this:
If you retired at a historical market peak, that will likely be one of the bad sequences. Yet, FIRECalc will show that a WR of ~ 3.2% will be 100% safe (historically).
Assuming our retiree has a fair slug of equities in his AA, we know that retiring at time when they have been bid up to very high valuations increases the chance of a nasty dip, maybe in the early years, that increases the chance of portfolio failure. Now, our very general rule of thumb (95% survival rate) is based on a broad data set that includes all types of starting valuations. If we instead used just those cases that started in periods of high stock valuations, then our success rate would be lower. Assuming a normal AA, what this "ratcheting" we're talking about does is to deliberately reset the the withdrawal amount after during periods of higher valuation (because that's the main thing that causes the portfolio value to spike, and which will trigger a "re-ratchet")--never down, only up. Is it realistic to think that the "general rule" 95% survival will apply?
"Old man, I'm told you track the success of all boats which sail from this shore to cross the ocean. I want to do that. What are my chances for success?"
"Well, Young Snapper, 95% of the boats I've tracked over many years have made it across. Big and small, fancy and plain--overall it is 95%"
"That sounds great!. Are there some boats that do less well?
"Yes. The boats made by the "Very High Valuation" shipyard fail to make it across at a much higher rate. They are loaded with nice things inside--cappuccino bars, heavy brass ornamentation, etc. They sit low in the water, and when a storm comes up, sometimes they have insufficient freeboard. That's how you can tell the most luxurious boats--they sit low in the water."
"Noted. They sound like very comfortable boats. Here's my plan: I'll set sail, and every time I see a boat that sits lower than the one I'm on, I'll trade and get aboard that one. I'll keep trading for more luxurious boats every chance I get. So, old man, my chances are still 95%, like you said, right?"
"Hmmm. Would you like to play a little poker before you set sail?"
I realize I sound uncomfortably like H***s!