DF8D00DD60AD00DD09208D00DD

$DF + STA $DD00 + RTS + LDA $DD00 + ORA #$20 + STA $DD00

$DD00 is a hardware register, where one typically set/unset/read individual bits.
Having a set of trivial helper subroutines to set/clear individual bits (or groups of bits) is an obvious solution (thus not copyrightable), some similarities are unevitable.
Besides, in this case (since the similarity does not even cover a single subroutine from start to end) it is clear that the similar code actually performs slightly different actions.