Sleepy, we are talking about saving after all expenses, right? All these tickets, kids' education , etc. are out of calculation. What I have done is simply deducted furniture allowance (3750) from your expected saving in Qatar (14200). so now your saving based on your calculation is not 14200, but 10450 which is CAD 2985. Now compare it with your saving in Canada.
Besides, I am not sure what do you mean by service cost up-front for the maid, but 500 QAR for twice a week cleaning service is definitely not enough. Each time will cost you at least 120 QAR, meaning about 1000 a month. Add transportation ( in case you don't pick her up and drop her off) about 200 QAR a month.