In pokemon platinum when you release the 3 legendary birds ( which are frames 1,6,11 respectively) and you're rng abusing for say moltres at frame 1, do you count the other two as roamers. For example my frame is 867 is set as target, and accounting for the monster frame, is it... 867-1-2(number of roamers) = 864??
If none of the birds are roaming when you boot up the game, don't count them. So in your case you would do 866 advances. If you had Cresselia or Mesprit roaming already, you would have to take that into account.