Sep 1991-Aug 1993 ABC Fri 8:30
Aug 1992-Sep 1992 ABC Tue 8:30
Aug 1993 Mar 1996 ABC Fri 9:00
Mar 1996 ABC Fri 9:30
Apr 1996-Sep 1996 ABC Fri 9:00
Mar 1997-May 1997 ABC Fri 9:30
Jun 1997-Aug 1997 ABC Fri 8:00
Sep 1997-Mar 1998 CBS Fri 9:30
Jun 1998-Jul 1998 CBS Fri 9:30

I have to admit I watched both Step By Step and
Family Matters when they were on ABC,but stopped watching
both shows when they were moved to CBS.
I think CBS was trying too hard to copy the success of
ABC's TGIF with their own Friday Night Block Party.
Personally I think ABC HAD the right idea with TGIF by airing
family friendly sitcoms.