Dear Gopal,
I think that you still need more explanation about the difference between "spread over" and "daily hours of work."
Like I said earlier, spread over refers to the total number of hours an employee is kept at the disposal of the employer, which includes the actual number of hours of daily work and the interval for rest. Spread over differs according to the relevant provisions of the establishment-specific labor law. For example, the spread over under the Factories Act, 1948 is 10 1/2 hours, whereas under most State Shops and Establishments Acts, it is 12 hours.
On the contrary, daily hours of work refer to the actual number of hours an employee shall be required to work, which is normally 8 hours, excluding overtime work. The weekly hours of work, therefore, become 48 hours only.
In your case, the spread over is 9 hours a day [9:00 hours to 18:00 hours], and excluding the one-hour lunch break, your actual daily hours are only 8 hours a day. If you are asked to work beyond the 18th hour, that alone would be treated as overtime. But the important point is that the total number of actual working hours shall not exceed 54 hours in total. This would imply that an employee cannot be required to work more than one hour of overtime on all the six working days.
However, if the contract of employment or the service regulations has fixed daily hours of work less than 8 hours, the extra hours, if any, required to work beyond the normal working hours thus already fixed, would entitle the employee to overtime wages for such work.