Tajikistan is about 3,000 meters (9,800 feet) above sea level.
Kyrgyzstan's AVERAGE is 2,750 meters above sea level. It ranges from 7,439 meters (24,406 feet) all the way down to 1,500 meters (4,921 feet) above sea level.
Written during the late 1500's and takes place in the 1300's
In this scenario, yes, you should wait. If you know that there is a possibility that you won't even show up and that there will be extra seats anyways, there's absolutely no reason you should rush to buy the tickets and risk wasting money.