How old is old? Maybe some of the older phones might not have as accurate GPS thingies? (I actually have no idea about hardware I'm just wildly guessing XD).

You could always do the alt account thing if you're worried about flooding people's feeds? Though I know of some who do 4 posts a day or sometimes even more so I don't think an extra one is going to hurt too much (well at least it won't bother me too much anyway XP).

Have fun with this new thing :)