A variant cover can quote a famous printed splash, swap a palette to yellow and red, or drop the web-slinger into a pose that never happens in the interiors. All of that can be delightful. None of it is automatically chapter two.
When we brief a drop, we ask one question: if this file disappeared, would the alley conversation still make sense? If yes, the file is showcase. If no, it is story. Costume gags almost always fail that test, which is fine — they belong on the wall as art, not in the spine as plot.
Evening circles in Bishopsgate put the story file on the projector first. Showcase covers come after the last panel, when people want to talk inks rather than continuity.