Statistically, 650TH should hit a solo block in 3.78days or sooner with luck (Like in this case), right?
Indeed, but (s)he hit 2 blocks in less than 2 days.AKA Long Shot...
If it's indeed rented then you only have a paid window to catch such a haul. Rent prices are set so you can't earn without hitting a block. So if you don't call it luck then use whatever term you like; I still say it's a Long Shot.Well, sometimes you either get lucky with a rental even on a non solo pool (I have), or just rent lower than you earn with a standard pool using your own miners. This is possible also.
You have to rent a LOT and be able to back it up with your own rigs, but there is a pay-off of a few extra % points at the minimum if done right.
Heck I've rented a large sum for short period before and hit a lucky stream to 3x my costs, and also rent miners cheaper than mine are earning, so that extra few % ads to the daily grind, so to say.