If there are 2 cars like yours in Alberta, then what is her argument for why they won't work? Is it a legitimate argument, or is she unwilling to use them because they are too high?
If you feel she is being unreasonable, then tell her that you already found two comparables and feel that they are the the closest you can find in Alberta.
So long as you are being reasonable, I would stick to your guns. They have to settle with you eventually.
Also, your thread title is basically non-sensical. If I were her, I'd lowball you for your inability to write a clear and concise title.
