The following section of the Employment Act may answer your question:
"(3)(a) For any overtime work carried out in excess of the normal hours of work, the employee shall be paid at a rate not less than one and half times his hourly rate of pay irrespective of the basis on which his rate of pay is fixed.
(b) In this section, “overtime” means the number of hours of work carried out in excess of the normal hours of work per day: Provided that if any work is carried out after the spread over period of ten hours, the whole period beginning from the time that the said spread over period ends up to the time that the employee ceases work for the day shall be deemed to be overtime.
(c ) For the purposes of this section, section 60, section 60D(3)(a) and section 60I, “normal hours of work” means the number of hours of work as agreed between an employer and an employee in the contract of service to be the usual hours of work per day and such hours of work shall not exceed the limits of hours prescribed in subsection (1). "
From the above, I think the employer in your case is not liable to pay overtime as the 48 hours limit is not exceeded.
If you are still in doubt, consult the Labour Department.