Configuration - Boss Extrude - Pipe

I have a sketch of a pipe (2 circles).  I've extruded it 1', so now I have a 1' piece of pipe.  I want to create another configuration of this piece of pipe, making it 12' long (I'm going to use both configurations in the same assembly).

Can't I simply change the extrude length and add a new configuration?  When I do this, and toggle between both configurations, they're the same... Whatever my extrude length is at the time, they're both that length.

I'm new to configurations, and I've searched the forum some, but can't figure out how to do what I want to do.

What am I doing wrong?

Thx

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