Strange loft behaviour - loft a tube

[RTschaggelar]

While a tube can be made by extruding a ring, meaning two concentric circles, the same is not true for a widening tube. I cannot loft a ring. I have to place a circle onto the tube on the outer diameter, then another circle whatever distance away. Then I can loft these two circles to get a solid plate Then I have to place a circle onto the original tube on the inner diameter, and another circle whatever away, and negative loft this pair. I gave it several tries, but only the approach with 4 independent circles worked.
Did I overlook something ?

 

[HaroldL]

Loft will not allow double sketches, like concentric circles. Loft to create the OD, single circle sketches, of the tube then use Shell to remove the end faces and create the ID with the shell.

 

[dwc]

Loft will not allow double sketches, like concentric circles. Loft to create the OD, single circle sketches, of the tube then use Shell to remove the end faces and create the ID with the shell.

Or use a loft cut to remove the interior if you need walls that have changing thickness.

 

[NateLiquidGravity]

Or if symmetrical you might loft half the "tube" and mirror it.