Uh, Never heard that greasing the sides of the pans made domed cake tops.
I place a barely dripping old, clean, 100% cotton dish towel flat on a cookie sheet. Then I put my pans of cake batter on top of the towel, then push the wet towel up against the outsides of the pan then place in the preheated oven to bake. The top comes out flat, the bottom corner is pleasantly done and the top edges and flat bottom are not over-cooked, nor are the sides pulling away from the pan. I pull my cakes when they test done with a toothpick or skewer.
I think that for a lot of people, their ovens run hot and metal conducts heat. The edges of the cakes cook faster than the center. The edges stop rising but the center does not, and this gives a domed top to the cake.
I used to have strips that were soaked in water then wrapped around the outside of the cake pans before baking to give a flat top. They worked great and I used them for years, but then they wore out so I went to the wet towel thing above. Works just as well as the strips and it is cheaper. I wash the towel when done and maybe wipe the cookie sheet off and that is it.