KPN is one of few operators who has bus service from Hyd to coimbatore, and to me you will regret if you chose KPN over any other operators.
There are multiple reasons to back my comments. First of all due to permit issue they will change multiple buses during journey, it will be mostly in midnight after 1 am in morning in some lonely highway places where anything can happen, definitely not recommended if you are travelling with family.
They will give departure time as 4pm and will leave from city at 7pm so ideally you are just circling city for 3 hours, which is utter non sense. And condition of the bus is really pathetic.
I will not be recommending KPN as your tour operator during travel.