If they match you do not get the message.
If you want matching settings drag a clip from the project panel into the New Item icon.
See this thread for screendump (not at my own pc right now).
OK, I guess that was part of my question (s) - does it make a difference that
the settings match or not? - you said' "if you want" - and i'm not sure if i want
that, if it counts, what the difference is; maybe not that big a deal in the 1st place?
Matching sequence settings is usually the way to go.
If you want to add the Warp to a clip that doesn not match you have to nest first is one of the things you can come across.
In the media browser select a clip, right click and then select new sequence from clip
Your new sequence then matches the source