That is one of the best articles I have read in a while. That is where I got the idea of using it at first and then ungrouping. Later down the page it reads
"Now we have almost all of the images aligned in one component. We can finally refine cameras alignment. To do this, we can ungroup all images and run final alignment. During this step, RC will count all the cameras as different lenses, and adjust the small deviations from the different zooms or sensor/lens shifts from optical stabilization (if you used it).
During this step, we can decrease the minimal re-projection error. By default, it is 2px. While it is good enough for most datasets, my personal preference is to refine cameras to the at least 1px error. Setting it lower will give a more precise alignment in the mean and median errors. Fewer errors – better mesh, better mesh – less work in post-processing."
This was the last step I described in aligning that trouble some bathroom with the repeating pattern on the walls form your other post,