Also worth mentioned that Nintendo reported that "Switch had its best week ever in US",
that means bigger even launch week in US, so we talking about great numbers in any case for just that one week.

This. We'll have to wait for official and homogeneous definitive numbers, because every PR department is deliberately mixing different parts of the period between the Monday before BF and CM, and chosing the most favourable comparisons to get the best spin they can. We could try and desume some things from PR words themselves, but if and only if they are correctly using the language, and this is not granted, and if they don't use any ambiguity, but alas about this we can be almost sure they do, instead.

This reminds me of their Mario Kart 8 Deluxe PR from last year.

REDMOND, Wash.–(BUSINESS WIRE)– With more than 459,000 combined packaged and digital sales in the U.S. on launch day alone (April 28), Mario Kart 8 Deluxe for the Nintendo Switch system is the fastest-selling game in the long-running Mario Kart series....The solid sales numbers for Mario Kart 8 Deluxe equate to an attach rate of 45 percent – meaning nearly one in two Nintendo Switch owners in the U.S. purchased a copy of Mario Kart 8 Deluxe on the first day it was available.

https://nintendoeverything.com/mario-kart-8-deluxe-sells-459000-copies-in-the-us-on-launch-day-fastest-selling-mario-kart-game/

April NPD wan't out yet so people used that attach percentage to figure out what Switch sold in April. If 459k was 45% of US Switch sales that meant that Switch was up to 1,021,000 units, meaning Switch sold 115,000 throughout April.

Switch ended up selling 280k in April, according to NPD.

But we do have official numbers ? (8.2M units in the US as of Nov. 26) 

Not much reason to question their internal figures in doubt when they have they most advanced methods of all which is tracking Switch systems themselves ...

Thos 8,2m does not count the days of november before the 21. I might think it's just the last NPD + the black friday numbers. There are more numberts to be seen. This PR bullshit is driving as crazy trying to figure it out the numbers. NPD can't come sooner

In the words of Shane McMahon misquoted from the 2000! Which way will it go!

Where's everybody getting their 800k figure from but more importantly how did it originate ?!

Great news, with this data sales, they can improve on stock availability for future sales prediction.

First, LT NPD numbers without November are around 7.3m, while Nintendo said "more than 8.2m" currently, that left around 900k difference. Second, Nintendo said best 5 days in for any console better even Wii, so Wii had one week with 800k, so people asume better than that, and 800-900k difference fit in calculation but only if we count those 5 days reported November period for Switch, not for hole month.

Yeah this makes most sense because around 800-900k difference with that calculation, fit with best 5 days even better than Wii, fit with 115% difference and best weeks for Switch (better than even launch week), while anything else doesn't seem likely because would mean Switch is selling similar like did last November, while everything points that Switch has much stronger month in any case compared to last year. But yeah, I guess we will need to wait NPD numbers.

That doesn't answer my question, again where did the 800k figure originate from ?!