Oh that's really strange, I would have thought this would be a much requested feature since it would make developing for multiple platforms much more straightforward.
Right now I have to manually create sprites of different resolutions for every spritesheet platform, it's fine since I can keep doing that, just surprised people don't think it would be nice to have it automated in the workflow to avoid having to change the size of sprites themselves when creating spritesheets for multiple platforms :-/