That Fundamental Principles of Communist Production and Distribution is really terrible, almost as bad as Parecon. As a blueprint for a labour-money economy it had already been criticised in advance by Marx in his writings against the advocates of labour-money (as an attempt to measure socially-necessary labour directly) of his day. No wonder Kautsky (who would of course been aware of Marx's criticisms) argued that, if you are going to go down that road (of accepting the terms of Mises's "economic calculation argument") you might as well use money and the market.
As to the slogan "from each according to their abilities, to each according to their needs" (which apparently you don't like), you are wrong. It was not coined by Saint Simon. His was more "from each according to their abilities, to each according to their deeds", ie what Stalin claimed happened in Russia and which both the Fundamental Principles and Parecon accept and indeed is the rationale behind piecework wage-labour. Its origin is generally attributed to Louis Blanc but was also used by Etienne Cabet. In any event it was current in the 1840s in Paris and it will be from the time he spent there then that Marx will have recalled when he wrote his notes on the Gotha programme some 30 years later.
I'm surprised you call in Mattick to refute it as "uncommunist" since in the very article he wrote in 1970 that you refer to he does say that today there is no point in tying consumption to work done but that society can go over to a system of free access according to needs,
As he says in the original German (since you refer to the German version) he writes:
In den hochentwickelten kapitalistischen Ländern, d.h. den Ländern, in denen sozialistische Revolutionen möglich sind, sind die gesellschaftlichen Produktivkräfte weit genug entwickelt, um einen Überfluss an Konsumtionsmitteln zu produzieren. Wenn man bedenkt, dass sicherlich mehr als die Hälfte aller kapitalistischen Produktion und der mit ihr verbundenen unproduktiven Tätigkeiten (ganz abgesehen von den vorhandenen unangewandten Produktionsmöglichkeiten) nichts mit dem menschlichen Konsum zu tun haben, sondern einem ”Sinn” nur innerhalb der irrationalen kapitalistischen Gesellschaft finden können, dann wird ersichtlich, dass unter den Bedingungen kommunistischer Wirtschaft ein Überfluss an Konsumtionsmitteln erzeugt werden kann, der eine Berechnung individueller Anteile überflüssig macht. Die Aktualisiemung des schon haute potentieli gegebenen Überflusses setzt allerdings eine völlige Umstallung der gesellschaftlichen Produktion auf die reelen Bedürfnisse dem Produzenten voraus.
Or, in English from this site:
In the advanced capitalist countries, that is, in the countries where a socialist revolution is possible, the social forces of production are sufficiently developed to produce means of consumption in overabundance. More than half of all capitalist production as well as the unproductive activities associated with it (totally disregarding the productive forces which are not exploited) surely have nothing to do with real human consumption, but only make sense in the irrational economy of capitalist society. It is clear, then, that under the conditions of a communist economy, so many consumption goods could be produced that any calculation of their individual shares of average socially necessary labor time would be superfluous. The attainment of a state of abundance, already potentially realizable, presupposes, however, a complete transformation of social production, based on the real needs of the producers.
So, I think Mattick can also be counted amongst those who want a moneyless society.