Oh yes, it’s not uncommon for mixing and mastering rooms to need different bass shelf targets. Here’s a thought experiment for you: Consider a mixing and a mastering room with everything identical, down to loudspeakers, distances, wall construction, etc. But still for reasons that you should be able to guess, the mastering room typically seems to need a slightly different bass frequency target level than the mixing room. Why do you suppose this is the case? Because it is!
