You should like from wherever you want to see posts, and if that’s your business page then that is where you should like from.
I always like from my personal page, and sometimes mention the 'so it will count" bit, but usually only to newbies to fb to help them understand how it all works. It’s not intended to be a demand for a return like as that would be down right rude.
That said, I think the number of likes does matter, it’s highly likely to be worked into the fb algorithm for showing your work on likers pages, so if you can like from your personal page then it does help.
I use fb an awful lot on my personal page, I interact witha lot of fellow artists and find it a huge source of inspiration and motivation. And most of my sales come in via fb, so it works well for me.