These are my spins since the April 2 update, but they do include the weekends. If the monkey items/horns/tattoos replaced other common/uncommon items instead of just being added to the list, it wouldn't affect the number of lamps received. Then that's pretty much useless for the purpose. It's not useless because the extra horns/tattoos/monkey stuff doesn't affect lamps. In the 13 possible rewards from a spin, there is always 1 unassigned small, 1 assigned small, 1 unassigned medium, and 1 assigned medium lamp. The only real problem with it is it's a small sample size.