When loading an hotel you must have a clear structure on the rates you are going to load. In our system you have to load a rate and inside the rate are the seasons.
Failing to do it this way may result on no availability if you confuse rates and load them like seasons. If your load 2 rates and you search for that hotel for dates that include these 2 rates it will not give availability.
For example, you have an holiday hotel that opens only half a year. Then you would have to load a rate for the whole opening period and then several seasons with their specific prices within that rate. For the next opening period then you should load another rate.
But if you have a urban hotel that opens all year, then you must load a unique rate and then add seasons for the whole sale period and keep adding new seasons when you open new sale periods.