The duration of the Boot Camps mentioned on the website includes the day of arrival.
The balance days account for the day of arrival, Sundays and holidays. In Regular Track and Fast Track, these also include days when you need time to prepare for the exams. In Super Fast Track, due to time constraint, full day for exam preparation is usually not possible.
In Delhi or Goa, for example, if the duration of the Boot Camp is 20 days and is scheduled to start from March 7th, your day of arrival will be March 6th, and last day of the Boot Camp will be March 25th. You can fly out on the evening of March 25th or morning of March 26th. If you calculate, you will be in India for exactly 20 days / nights.
In Shimla, if the duration of the Boot Camp is 20+2 days and is scheduled to start from March 7th, your day of arrival in Delhi will be March 5th, you will travel to Shimla on March 6th and last day of the Boot Camp will be March 25th. You will travel to Delhi from Shimla on March 26th and can fly out in the evening of March 26th or morning of March 27th. If you calculate, you will be in India for exactly 20 +2 days / nights.
You are most welcome to arrive a few days earlier or depart a few days late (accommodation will be charged extra according to your choice of Hotel).