If you are covered under Part IV of the Employment Act, you will be eligible for OT under the Act.
The Act states that OT calculation for monthly-rated employee will be based on:
(Basic Salary x 12 months) / (52 weeks x 44 hours per week) * 1.5 times
Thus, even if you work less than 44 hours a week, OT will be calculated based on a 44 hour work week.
Reference can be found under my Page “Sources”:
Hours of Work