well when he died he was in it an extra 2 times despite that obvious handicap of being dead
even if once was in the home movies martha is watching, they werent reused stock footage so it would've still classed as him being paid to appear
and of course the episode where clark sees him in the afterlife when he gets told to bring him back someone must die, which... didnt clark die once before too? so erm if his dad wasnt dead at that point who did he see then?
amusingly though, johnathan kents dead yet still gets his pic in intro yet it took lionel an entire season before he was bumped to intro status