WRT Taxes in Canada:
The Overseas Employment Tax Credit (OETC) is very simple, if you work for a Canadian company outside of Canada in an approved function, ie offshore exploration, UN, Tourism for at least 182 consecutive days, you will receive the credit. Now when I say 182 days, you don't have to be out of the country for that period, it simply means that your income is derived from a source outside of the country for that period.
Physical presence laws do not apply. It's very simple:
If you earned $80,000.00 dollars in a year, 80% of the Federal and Provincial taxes are waived or tax free. This leaves 20% of your income to be taxed. In this case, 20% of $80K is $16K at the lowest tax rate. This equates to about $3000 total tax payable or about $77K take home.
Now if you are working in Canada, then you would be subject to full taxation, or about 46% in Ontario. This, I would agree is a very heavy tax burden.
Hope that clears things up.
Cheers, OffshoreIgor