It seems to me then your definition of "diseconomy" is pretty arbitrary - I mean, do you include private profits of the owners? Presumably not.. but why not? What's the difference between renter raking in profit, between CEO having bonuses and golden parachutes, and between a bureaucrat creating useless work for himself? Aren't all these diseconomies? And if you accept that, then eventually whole human existence becomes one big "diseconomy"..
To me, "diseconomy of scale" is a weird concept, and I think it's because it actually has to be normative. This is unlike "economy of scale", which is well-grounded; if I want to make one car, it's not efficient to build a production line first, but for million cars, it can be. So when something is subject to "economy of scale", it is because there are more possible economic solutions; however, I fail to see how something could be (in the physical, and non-normative, sense) subject to "diseconomy of scale" - surely you could in that case just duplicate the original small-scale process as needed (in other words, why would the corresponding "reduction of possible solutions" happen?).