... its at most 5 years from worst vs best... so planning for a 2 year range is all thats needed for the most part. and even then as stated knowing this is great but there is no way to effect what happens over your accumulation window. so just dump in the money and decrease your spending and retire when you get to your number and you're comfortable with the current status of your investments to support you.

I agree. And I think this is really sort of akin to discussing whether the glass is 80% full or 20% empty.

this also assumes investing the same amount annually. Most investments accellerate throughout life esp. around here in 7 years my salary has gone up 120% so this would need to take into account non linear investment on an annual basis i'd be interested to see how a 20% increase in investment YoY affected the best and worse outcomes

You could pretty easily modify the stock market monte carlo simulation worksheet I provided

here to do that. Well, except for estimating the inflation rate. But if you worked in nominal dollars which maybe works okay for a shorter forecast, that might be okay.