For now, keep it as airtel billingAlso, my neighbours, family, many especially elderly people ask me the question. I recharged for 30d but get only 27d or a lower validity ? Most of the time they have add-on or VAS activated in their plan. They don't understand thier plan. I think DTH billing is getting complex day by day and it wouldn't be a surprise if a diploma will be needed to understand the billing.