1 Gallon Recipe

I just brewed my fourth one gallon batch. When I looked at the 5 gallon batch for the beer with the identical name, there were totally different ingredients. Can you take a 5 gallon recipe and scale it down? Or do you have to make other changes because of the smaller amount? I think I would like to try some different recipes beyond the standard kits so what is the best course to follow? Thanks for any ideas.

I’m guessing the one gallon batch was from extract with specialty grains and the 5 gallon batch is either partial mash or all grain.