Maybe he was, maybe he wasn't, I'm not a Tito expert, if he was then he should have known better, goodness sake even Langes the father of it redeemed himself when he realized he had fallen into a rhetorical trap set by Mises

But either way I hate to break it to you the Lange model was the only "coherent" theory the marketists could muster, the Austrians were correct about one crucial aspect, parasitical capital finance is the motor that makes the market run, it's why certain market socialists like Lange, Kamikazed themselves to bring down Hayek by pointing out inventory input/output planning was already developing internal to capitalist firms and along interfirm networks and under socialism it would develop further, this was the 1930s the Austrians lost the debate and Hayek quite literally went insane and exiled himself to self-publishing

Even Austrians give the game away when they praise the likes of Frederick Winslow Taylor and Kōnosuke Matsushita, it's not a matter of whether non-market calculation is possible, it's always been about what type of calculation and for whose benefit as this gross-ass quote by a top Austrian so aptly demonstrates

Darwin, Marx, and Freud make up the trinity often cited as the "makers of the modern world." Marx would be taken out and replaced by Taylor if there were any justice... For hundreds of years there had been no increase in the ability of workers to turn out goods or to move goods... When Taylor started propounding his principles, nine out of every 10 working people did manual work, making or moving things, whether in manufacturing, farming, mining, or transportation... By 2010 it will constitute no more than one-tenth... The Productivity Revolution has become a victim of its own success. From now on what matters is the productivity of nonmanual workers. -- Peter Drucker, The Rise of the Knowledge Society Wilson Quarterly (Spring 1993) p.63-65[15]