Did you use the <F4 key to change the addressing style when creating the
formula?

In other words,
=IF(A1=1,B1,C1)
....will adjust all references when copied or filled down the column.

=IF($A$1=1, B1, C$2)
....will NOT adjust the $A$1 reference and WILL adjust the B1 reference when
filling down. The C$2 reference will NOT change the row number of when
filling down, but WILL change when filling horizontally to the right or
left.

Select each reference, then press the <F4 key to cycle the reference style
from absolute to relative (there are 4 different combinations).

--
Regards,
Bill Renaud