Inconsistent sizes for objects

[MBrownFPTRT]

In the attached image, the extruded Box, shown in pink, measures 10'0" tall. The extruded spline (which, despite  Caps box checked and Auto weld turned on and set to 1" is still showing open ends) measures 1' 3 and 4/8" tall (yes, that's right: 4/8"). As you can see, these objects are actually the same height. I'm not sure I understand what is going on here. Can anyone explain why the Z axis has a different scale from the X and Y? It is a new document, so all the defaults should be in place. The spline is an imported AutoCAD drawing and it matches the X,Y dimensions of the AutoCAD file from which it came. This is a little distressing from a precision point of view, so I'd be very grateful for any advice.

Thanks,

MH Brown

[BenBisares]

If you select the spline and use the scale tool, is the value set to 100? It seems like there is some scaling issue going on.