This may be the case. Basically it depends on the visa officer- they may or may not look at the proof of the insurance coverage.
Best way to go about it is to get a full coverage and then if you become eligible for provincial coverage- you can get a refund for unused days.
Here you can find more information about the options available:
<a href=http://arbetovinsurance.com/iec-travel-insurance/>IEC/Working Holiday Insurance</a>