Non power of 2 question with pixel painting

Im developing a painting on textures app for the iOS. The texture size is a 4x12 and when i start painting on it the pixels bleed because its not a power of two texture. So I went ahead and set all the textures to advanced - Non Power of 2 to nearest. Everything working fine till i need to export their file. I have a template that I have to follow and when i set the offset x and y to where the textures need to be placed its a 4x16 because the power of two which overlaps some other textures. Is there anyway I can turn power of two off or something? New to unity so alittle confused here.