It's not about mistakes calculations, it's just to go forward. And I've did a mistake with direct color calcs too (see r5431). OPT cases (both gfx mode 2):

Dead Dance, Rolf stage (6):
[Linked Image from]
(rocket actually moves with the sprite)

Super Double Dragon, later in the stage 1:
[Linked Image from]
(there's actually another elevator on the right, people enters from the glass "hole")

Still don't have a plan for OPT frown