Payment by separate challans would have been better as then you could have shown the interest paid per quarter more vividly. but even now if you have mentioned the details correctly and paid the interest correctly there is no problem
Abatement has been provided in those cases where there is a combination of services and sale. As only services are taxable, exempted part of the services is on account of sale involved in the contract. Hence this value should not be taken into account while computing the total value of the services for the purpose of falling under the SSI notification.