Making sure the rotation of the objects I'm looking at is the same is obvious, whether or not a column is mirrored is however not. Place a profile shaped column, make the angle 0 and then hand it, the handed result also has an angle of 0. Same type of object, same rotation, different result.
Knowing that now and checking again but doing a different process, using a favourite tool that inserted a simple square column, then applied the custom profile to it (making sure rotation was 0), the result using my L shape profile was the way it should have been, so it seems that the favourite tool inserted a column that was handed from the start, so when I was applying my own profile it too came in handed.
Looking at that raises to questions for me:
1. How can you check a favourite tool to see what it is set as, because I couldn't see anything? If you could see it I can imagine you would also be able to edit the various properties?;
2. If you have an object like a column that doesn't have a "Flip and Rotation" property (like objects seem to) how do you know if it is handed?
Not that it is likely to ever be a consideration in real life....