Any organization, whether it is related to business or otherwise, is a collective endeavour of people and material resources and the subsisting contract of employment between the employees and the organization is an arrangement to ensure uninterrupted co-existence. Notice of unilateral termination of the contract of employment from either side, the employer as well as the employee, necessitated by one's expediency and convenience, is, therefore, based on the principle of affording some time to the other side to make alternative arrangement to fill the void created by the premature termination of the contract. Of course, the period of time stipulated in this regard in terms of days or months and the payment of monetary compensation in lieu thereof can not be effective substitutes for the reason the loss to the organization with the sudden exit of a trained employee and the difficulty of finding a suitable alternative employment experienced by the employee are immeasurable. How ever vesting the discretion of accepting the proposal to buy-out the notice period with the employer is a matter of larger consideration in the interest of the organization. The exercise of the discretion by the management in favour of the employee in such a situation is conditioned by several factors like the position and responsibilities held by the employee, the genuineness of the reasons shown etc. If the reasons cited for early release are genuine and the responsibilities held by you are substitutable, well, I think that your manager's apprehension that it would set a precedent is unfounded. After all, discretion is the exercise of personal judgement befitting a particular situation based on its peculiarity. Better take up the issue with your top management.
3rd January 2016 From India, Salem