Minimum wages for maid in Singapore

Now, there has been some argument that there should be a minimum wage for maid in Singapore. This is mainly triggered by Philippines' Government who wants USD 400 (~SGD 525) as a minimum wage for their citizens who work as maid.

I want to examine the case objectively. Since maid or housekeeper is a profession, it needs to be compared with other profession of similar nature. In Singapore, I would argue that cleaner in the coffee shop should have a job similar in nature to maid, i.e. keeping things clean. After all, Ministry of Manpower in Singapore theoretically says a maid should be asked to do only one job scope, i.e. if the maid is to keep house clean, he/she cannot be asked to take care of your kids.

I understand the cleaner in coffee shop is normally paid SGD 600. Considering that they are paid for 8 hours work while maid normally work up to 16 hours, the equivalent wage would be SGD 1,200.

Currently a maid from Philippines in general is paid SGD 350 a month. However, that would have included accommodation, meal and other expenses. If I put in monetary value into those:
- Accommodation of one room without air conditioning and relatively poor condition (admit it, only very few employer give their maid an accommodation fit to be paid normal rental): SGD 300
- Meals, assuming SGD 3.00 a meal and 2 meals and 1 breakfast (SGD 1.00): SGD 7.00/day or SGD 210/month; say if you give fruits and others stuffs, maybe I will round it to SGD 230
- Toiletries and other expenses: assume SGD 30/month
- Travel expense: assume SGD 40/month

The total expense for a maid excluding wage is then SGD 600. If I would to include wage, in total it will become SGD 950. However, there is still levy to pay, that is around SGD 170 (with concession). That means, an employer's effective cost is SGD 1120. That is not that much different from what will be earned by a coffee shop cleaner. In fact some coffee shop cleaner may be even paid less. In fact, if the employer does not receive concession, there will be around SGD 80 extra for levy, making the cost the same.

If the minimum wage for maid is upped to SGD 525. It constitutes a SGD 175 increase. Using the same argument of cost, it would mean that a maid will earn more than a coffee shop cleaner. Hence, I would urge the Government of Singapore to also implement a minimum wage for coffee shop cleaner and other similar profession similar to a maid. There should be equality, right?