WBXZ-LP will continue to use  with ERP at 15 kW, meaning most of GTA viewers won't receive this signal due to Global's Toronto transmitter.
[Link: fccdata.org]

WBXZ-LP could become a full power class A station by moving to an available VHF allotment after the transition period ends in three years, but that would take money.

Global's Toronto transmitter on RF  will have a reduced ERP only because
"lower frequencies propagate better than higher frequencies, the power is adjusted down as the frequency goes down".  The contour range of most stations should not change when they change frequencies.  However, CIII-41 and WBXZ-LP contours lines do seem to conflict greatly in Western New York. Stay tuned.