The company is liable only to give you ticket as per the contract. But if you want to encash it for your own benefit - either you are getting the tickets from a different source like your spouse's company or redeeming the points.or may be taking the cash and enjoying a local leave. The company is giving you a favour of encashing your ticket.

Basically you don't have the right to complain if the company deducts a percentage of from the encashed ticket.