This, to me, is another reason why employing a feedback cycle and only relying on those estimates as a first approximation makes most sense.
The estimates won't take into account how dilligent you are: do you estimate how many meatballs there is per 100 calories, or do you guesstimate based on measuring once? do you count the calories in your sugar free chewing gum (it's certainly not calorie free)? do you measure out the amount of ketchup you put on your food and count the calories? And so on.
With a feedback cycle hopefully you're roughly consistent, and if you adjust on a weekly basis based on how you're doing you'll hopefully also counter-act your own self-sabotage (e.g. it's oh-so-easy to subconsciously take more of anything you've decided doesn't need measuring, like the above mentioned ketchup, or find yourself suddenly chewing 10x as much chewing gum...)
(at the same time, one of the benefits of these shakes certainly is that if you adhere strictly at least for periods, you take dilligence out of the picture; though you still need a feedback cycle, as e.g. differences in how much energy you have can easily affect your activity levels and so change your rate)
Anecdotes not being data and all that, both you and I had the same experience of that number being too high for us to lose weight. I don't have time to look for actual research on what the right averages should be, but the mor important point is that the averages are relatively unimportant:
What matters is not what the average burn rate for your build is, but what you burn. And you yourself is the source for that calorie intake being too high for you.
The averages matters for generc advice and as a starting point, but they can never be as good as measuring and adjusting.
And I think that is part of the problem with this advice. Too many people seem to influence their intake by it but then get surprised and dejected when they don't get the result they expect, instead of using their result to tweak their intake accordingly.
You've done a great job proving it yourself - despite only consuming 2000 calories, you were still gaining weight. Unless you weren't counting anything aside from soylent (drinking, snacks, etc) you were past your maintenance consumption.
