OpenTTD does give the alignment values of the cropped sprites when you encode your newgrf using nml's or grfcodec's cropping feature (as they remove the extra blue pixels and how can one tell what was the original value.
As you can see from this sprite
cropped_sprite.png [ 1.07 KiB | Viewed 1818 times ]
which is the exact one that the sprite aligner was pointed to, there are no excess blue pixels. There never were. I have no need of a cropping tool or feature mainly because I never leave anything to crop.
Decode your grf and compare with those values instead of those withing your original code).
Wouldn't it be much simpler if the aligner simply displayed the real value, the way it used to do?
Additionally it shows the values for the zoom level you are currently using - information which you conveniently cropped from your screenshot-snippet.
Considering that I did experiment before starting this topic and that I found the values remained the same for every zoom level, the conveniently cropped zoom level would have been redundant and perhaps even confusing.
I am sure that there must have been a good reason to make changes to the sprite aligner such that it now provides the fine tuning of one click per quarter pixel and displays values in quarter pixels. I simply do not know that reason. Perhaps someone could point me to the documentation.