We can all Google, so I can see you have not a grasp on this yet. Let me try and simplify this for you. The quantity you can mix is much larger, mixers are restricted in size, and varying sizes and so where you managed to google these silly stats I'm puzzled (and in reality they are wrong), the mix is mixed dry on the ground before water is added, not that much backwork is done once water is added and so forget the vision of guys turning over constantly as if a machine, this is not needed. Mixing dry is light work and thorough. Now you can add water into the centre of the volcano, right up to the lip and leave for 10 minutes (the water is absorbed into the mix) while you prepare another, once the other is prepared you come back to the initial and cave the sides in and start turning over quick, a couple of shovels is good, then barrowed and off. Hopefully you can see a cycle that now occurs and it becomes much quicker.
As for shovelling, well, with a mixer you are shovelling from floor, to mixer, why not leave on the floor and use that energy to turn it over and get a better result.
The quicker you get a mix down the stronger it is, that is just a fact.
I am telling you onsite realities here, after 20 years property development throughout Europe and to European standards I know what saves time and works well. The problem with google is much of the time it is great on paper, but in reality is not that productive.
I'm not debating this with you, I'm simply telling you how onsite is. You can view from your computer screen and continue to clean mixers out for an hour before knocking off time, doing pi$$y little mixes, having guys standing around waiting for cement half the day, that is your choice, to get the same productivity hiring 3 or 4 guys and mixers more than needed, jees (there is always method to perceived madness, if you don't know, some things are difficult to understand, hopefully you understan a little more now).
I prefer to keep my guys moving, and therefor keep the mixes coming.
And by the way, give me a mixer that will toss out a mix every 1.5mins, that is BS and if it is doing that then it is not mixed properly.
I am not going to debate the mixing method as you have yours, and I know whats better so move on.
Tell me about stretching cement? How does the method adjust the ratio?