Dear Anshul,
In private organizations, the atmosphere that prevails while taking ultimate critical decisions in any matter is quite informal. The people in the immediate link of the hierarchy have to succumb to the unwritten principle "The boss is always right" and execute the decision accordingly or quit.
Before finding an appropriate answer to your query, it might be relevant to get an answer to the following query: When the director has already informed his decision orally, what prevented you from asking him once again whether to reduce the salary of the individual by 20% or not while preparing the salary bill?