There are 3 parts to the state economic planning:
Technology: which ingredients go into which product in which ratios. E.g., given 1 tonne of Samotlor oil and such and such refinery design, this much gasoline/kerosene/asphalt is produced. This depends on the state of technology and quality of its implementation, and is not very specific to the USSR (chemistry works the same way under communists and in the free world).
Capacity: the specific oil refinery plant located in city X can process this much oil per day, and has such and such incoming and outgoing pipelines and railways. If I understand correctly, this is the subject of the question.
Optimization: methodology how to combine 1 and 2 to maximize production, new construction &c.
This is "simple math".
production capacity is a major state military secret
Production capacity indicates economic choke points, and, as such, is the major input for strategic military planning. In fact, the Strategic bombing during World War II was not as successful as it could have been because of inconsistent and/or flawed target selection (see Inside the Third Reich by Speer) because very little was known about the inner workings of German economy.
Thus this information was always classified in the USSR.
What was, in fact, published - СССР в цифрах ("USSR in digits") was, first, fake through and through, and, second, reported some information in absolutes (e.g., tonnes), some in percentages, and yet others in differences between other unknown quantities, so that making meaningful conclusions beyond "soviet economy is growing real fast" was impossible.
Nevertheless, the Western economist poured over those volumes of garbage which reduced people like Birman to tears of laughter.