Copy or moving a partition isn't working well

First I tried to move a partition and found that I couldn't do it, because it got shrinked to a size one unit smaler than the original one.

I could solve this in that specific situation as in the context you are able to change size to a bigger one as well and I did not need to have a precise copy in that case.

But now I had to copy a partition from one Drive to another without any change and couldn't do it. The fault is that because of alignment I did not knew which size I had to put in.

So in this step of the software is a fault where I suggest, that once they count maybe the last or the first Byte in and once out.

But I do not know where that fault is, as it seams that it is even if you create partitions. I thought that I did a few weeks ago a fault by typing in the size but now I know, that it looks like as if this fault is as well than working but you do not really realize as long as you do not want to create same size partitions. I recognised by doing this for a raid that I got a better result with sgdisk as with gparted but did not realize, that it isn't the alignment that changes the input as it looks like there is some kind of a fault that is in the whole input section.

Best you see it while copying a partition from one drive to another, as this should never get smaller as the original.

maybe I do something wrong but it doesn't look like it.