Hi Burr, yes that's normal - when you use the cutting curve, the surface that is generated from the cutting curve is an extrusion of that curve, using the whole curve. So if you have a long cutting curve then the extrusion generated from it will be just as long.

But if you want to shorten that surface, you can use ShrinkTrimmedSrf to shrink the underlying surface down to the active trim boundaries. ShrinkTrimmedSrf will not currently work on a face selection though, so you can either select the entire object or use Edit > Separate on that face and then run ShrinkTrimmedSrf on it and then rejoin it.

- Michael