Strange behavior in auto-arranging artboards

Steps:

• I create a simple artboard and position the 0,0 point to align with the upper-left corner of the artboard.
• I add several new artboards (which align horizontally with predetermined space between them)
• I then select Auto-Arrange artboards and enter 1 column.
• I expect the first artboard to remain at 0,0 upper left corner as it indicates both in the Auto Arrange dialog box and because that's what I setup to begin with.
• I expected the second artboard to be located at the height of the first artboard + 20px because I set that in the Auto Arrange dialog box.
• Since my artwork is 200px tall, the coordinates of the second artboard should be 0,220 allowing for the 220px gap.
• I return to edit my artwork to find that the first artboard is no longer at 0,0. It's at 57.5, 238.8 or something strange.

Please tell me what I am doing wrong and how this makes any sense at all. I never asked the first artboard to move, I explicitly set the 0,0 point and every single anchor is set relative to 0,0 for my artwork.

How can I get the Auto Arrange artboards function to honor my settings for the 0,0 point and to arrange artboards relative to the first artboard?

Is there any way to automate the creation of artboards withthe content of the first artboard for the various asset sizes for use in export assets?

I would like to have a single file with several versions of my artwork setup in a grid so that color pallets go horizontally from left to right and scales go vertically from top to bottom.

Is there any way to automate this or do I have to create it by hand and use it as a template?