Interference parameters and protection only apply within grade A and grade B contours. If there is an issue within Canada, the US LPTV station will need to make changes to eliminate it. If the Canadian stations are outside the protected contours in Ft. Erie then it doesn't matter.
The FCC doesn't use TVfool.
Neither does IC. They use contour maps that are much less sophisticated than the algorithms used by TVFool. Due to local geography, there are areas here with reception that is significantly different than the FCC and CRTC contour maps.
Fort Erie is within Global Toronto contours.This would be new interference.The CHCH interference was a pre existing and accepted by CHCH.If you go by percentage of population than it would be within limits.Left as is pretty sure reception will be lost by many in both countries for RF 17.