Are you talking about the practice being followed in Kenya? sorry I have no info.to offer you ready answer. However in India, 'buying' the inserved notice period if compensated by paying the emoluments at the rate at which what rate the employee would have drawn had he continued in the employment is agreeable. There could be exemptions & exceptions at the discretion of the employer. Some would agree with- limited to fixed components like Basic +DA +HRA leaving other variables out. Similarly where CTC pattern is followed. There is no hard and fast rule. It depends on the practices/polices followed by the employer.
If you have not communicated to your HR /management as yet try to send an email asking them to waive the balance notice period as a first step. Depending on their response you may take further steps. As already informed by the learned member it all depends on the company policies and if there is none, the discretion is left to the employer.
Be polite and diplomatic and also inform that you are available in case of any handover formalities with an mutually agreeable date[s] to see that the works are not affected.
Thanks and Regards