--+---------+----------+
  There doesn't seem to be a difference to the legal SBC.


 4510 Versions:

  +----------------+-----------------------+---------+---------+----------+
  | Addressing Mode| Assembly Language Form| OP CODE |No. Bytes|No. Cycles|
  +----------------+-----------------------+---------+---------+----------+
  |  <A HREF="ADDR9A.HTM">(Indirect,X)</A>  |   SBC ($FF,X)         |   $E1   |    2    |    ?     |
  |  <A HREF="ADDR4A.HTM">ZeroPage</A>      |   SBC $FF             |   $E5   |  