I don't think that is how the planned economy works. I mean, it is true, that it is computationally intensitive, that is why one of the factions in pre-fall USSR was pushing for computerisation of the whole thing. If they prevailed, then for a little while at least there were some sort of cyber-communism or cyber-socialism in USSR. :-D

Anyhow, but isn't it how everyone from small firms to bigger corporations operate, internally? They plan their budgets, plan their products, and based on how well that planning goes against some external factors they either succeed, or fail.

I think that demonizing planned economy is not the right thing to do. More like study it for its merits, and see where they can be applied. Writing off things without understanding them for ideological reasons isn't really efficient. :-D