Why classification is the point of attack in fraud cases
Article 159 is drafted broadly, and the parts of it are separated by the size of the loss and by aggravating features. The thresholds are absolute figures: significant damage, large scale, especially large scale. Because they are absolute, the calculation of the loss decides the part, and the part decides the sentence.
The other recurring question is intent. Fraud requires that the accused intended not to perform from the moment of the transaction. Non-performance that arose later is a breach of contract, and a contractual dispute is not a criminal offence. The Supreme Court addressed this directly in Plenum Resolution No. 48 of 30 November 2017.
Why cassation could reach it
Classification is a question of law, and questions of law are exactly what survives to cassation. A complaint asking the cassation court to take a different view of the evidence would have been refused; a complaint showing that the established facts do not fit the article as charged is within its powers.