The second reduced rate is identified by the elements "sumZklSniz2" (VAT base – 2nd reduced), "sumDphSniz2" (VAT – 2nd reduced), "sumCelkSniz2" (Total incl. VAT – 2nd reduced).
REST API VAT Reduced Rate Type 2
How do I record a second reduced VAT rate via REST API?
Written by Petr Pech