nice that they turned out fine Carl Aird!
GRK I think in cakes it can be very critical, some cookie recipes are not as picky as to how they go together. Did you ever have to do the experiment where you use three temperatures of butter and then look at the crumb of the cake, it can be very different with butter that was too hard and cold, and butter that's too warm. I was taught to bend the stick of butter, you want it to be able to bend nicely, not mush (too warm), but not break in the bend (too cold).