Yes, 1 keystroke at 50% zoom does equal a 2 pixel movement instead of 1 pixel as is the case at 100%. If you recall, I brought this up during the original beta test arguing the case that they should make it so that irrespective of the zoom level 1 keystroke should equal a 1 pixel movement, otherwise at 50% zoom your only option is to update the coordinate via the properties window or use the alignment options which I also pointed out don't always work properly at 50% zoom. At times using 50% zoom I discovered that when selecting a row of buttons and using the alignment options certain buttons might end up being 1 pixel off. Could not replicate the issue working at 100% zoom, only 50%. Discovered this when I was working up my initial XCF file using my TSU7500 PCF as a starting point. I also pointed out to the team how both of these issues could clearly be illustrated in their own stock configuration files which were packaged with the editor. There were numerous examples per the stock configuration files where when flipping from page to page buttons which were supposed to be positioned at the same coordinates from page to page where sometimes off by a pixel here and there. As a result, when flipping from page to page you would see a small shift in the positioning. This was clearly a result of the person working up those configuration files not realizing that at 50% zoom the alignment options did not always work properly and that 1 keystoke at 50% equals a 2 pixel movement, not 1. The team did end up agreeing with me that both issues needed addressed. Unfortunately they were not.

Now per my own configuration file...
At 50% zoom neither row of buttons snap precisely where they need to go per the cover image buttons for my A-Z pages. At 50% zoom the top row of buttons snap to grid 2 pixels lower then they should be. The bottom row snaps to grid either 4 pixels too low or too high. Additionally, at 50% zoom the grid spacing is much tighter making it easier to snap to grid way off the mark. At 100% zoom however, the top row of buttons will snap to grid precisely where they need to go with the bottom row of buttons snapping to grid 1 pixel lower then they should be simply requiring you tap the up arrow on your keyboard one time. The grid spacing of course is further apart at 100% making it very difficult to have a given button(s) snap to grid off the mark. As a result, at 100% zoom I can quickly and accurately jog a letters worth of buttons down without even paying close attention as I'm doing it. Pretty sweet compared to the ProntoNG days when my page layout didn't accomodate being able to use the snap to grid.