Hey! Thanks for reaching out. We aimed for a tileset that works properly with 64x64 characters (which are 64x64 for sure). But yeah, you are right. The single row needs you to use the space below as part of the construction, but despite that I will change the description so anyone got confused here. The tileset can be properly chopped as 16x16 or 32x32.
I am attaching an image with a 32x32 grid setting.