Bonus is a deferred payment since it is being paid any time during the year immediately following the Accounting Year for which bonus is calculated. Therefore, logically it should be a certain percentage on the earnings of the employee pertaining to the AY only. It follows automatically that minimum rates of wages pertaining to the locality where the employee worked during the AY only should be taken into consideration and not the location of his employment at the time of calculation/disbursement of bonus..
From India, Salem
This is to inform you that, bonus needs to be calculated on the basis of "seven thousand rupees or the minimum wage for the scheduled employment, as fixed by the appropriate Government, whichever is higher". Thus you may use the same process which you are following to all the employees keeping in mind the said stipulation.