[Question] Are the docs for ICP tutorial up to date?

[Question]
Hi, I'm trying to do reconstruction with PCL 1.8.1.
I've setup a project to do ICP and it seems to be working however I'm not sure what to expect regarding its output and accuracy.

So I tried the tutorial here :
http://pointclouds.org/documentation/tutorials/pairwise_incremental_registration.php

But the result aligned cloud seems off, as shown in the image below

As the white arrow points out, the stairs are not aligned properly. You can see the double image.

I expected the alignment to be better than this, so is there something I'm missing?

I didn't change any code from the tutorial except :

reg.setPointRepresentation(boost::make_shared<const MyPointRepresentation>(point_representation));

PCL 1.8.1 doesn't have memory.h for make_shared so I just changed to use boost's.

I don't think this makes a difference but I'm not sure.

Please advise if this is indeed the expected behavior or there are things I can do to make it better.

Thanks

Start with the pairwise incremental registration tutorial linked in the issue and compare its documented output with the reported PCL 1.8.1 result. Check the stated change from memory.h to boost::make_shared and determine whether the tutorial needs clarification about expected alignment or accuracy; done means the documentation or expected behavior is clearly explained.