LOL at mashed potato!
It's potato starch, in fact - I guess there is a factory process which removes the starchy (carbohydrate) bit of the spud and mixes it with the rice flakes and then chucks it into the skimmed milk and other stuff that make up the formula. Result will be a thickened, starchy formula, that still gets through the hole in the teat.
There must be a food scientist here on mumsnet who might know more about this.
Formulas are a commercial product and segmentation of the market is necessary to their commercial success - they cannot all jostle side by side in the market place and admit they are all basically the same.
It's a bit like washing powder - all basically the same, and they all used to claim that 'science' made them better than each other. Now, they realise that people have seen through/are sick of that argument, and so they concentrate on getting consumers to make a relationship with the brand, because of green credentials, nice perfume, special art sets for schools and so on.
Formula milks are similar, in that making a relationship with the brand is important, but they still use the 'science' bit as well. Spurious health claims are supposed to be illegal, but I note they are still making them.