Rental allowance for a CN on the old terms is about HK$100K a month, when you make CN in around 14-18 years this will probably be more than your total package including the housing you get as is tied to the government rental index, something nothing in this new deal is. It will be a fight every time you try to increase it and will probably lose as they then have you getting up the seniority list and know it would be hard to start again elsewhere. This is not just a short term thing, it is your whole career and soon the HK$36K will be insignificant especially by the time you start to get that amount if you are joining now. The reason the CN expat rental is high is because that is what a CN has to spend to live in a place he would expect to be able to with his family if he were a CN with a legacy carrier in his home country. Joining on the new deal it is very unlikely that you will ever be able to live in a house, ever.