Dear Robbo2A,
If by Commercial Flying Instructor, you mean the run of the mill earning an income flying instructor. Then I have some news for you.
The 40k per annum is a bit off the mark. The industry award rate for full time employment (if you can get it) is still in the low 20K AUD. That is junior Gr.3 VFR S/E. A CFI with Multi IFR testing may get 40K. I dont have the figures on hand but others would have a better idea.
What is the money you get in your part of the world?