When I ran those simulations it was before the budget so I didn't know what the government was going to do with GIS. It hadn't been clear. I assumed the OAS eligibility would be raised from 65 to 67, but the GIS would be kept. I didn't think the government would want to cut incomes for the poorest of the seniors in that particular age range, but in fact the bill does propose to do that. It changes the dollar amount of the savings.
There are clearly knock-on effects. If you have less income, there is less income tax paid, and there are less commodity taxes, sales taxes, GST, HST that are collected. There is a knock-on effect for the provinces to the extent that people go on social assistance to make up the difference, particularly if they have no other sources of income.
To reinforce comments of a couple of other folks, Arthur and Keith, it really is useful to look at this as a system, because there are these interacting aspects. The technical machinery exists to do it. I don't remember the numbers precisely since I only started at this last night again.