My comments were really pretty general, as these are two things I think were worth mentioning for anyone else reading this thread. I'm sure you probably have looked into these matters.

But as far as measurements are concerned, it can be kind of hard to get good measurements down low. In room measurements are notoriously difficult and you really can't trust them. Even if you know SPL at one position, move a few feet and you may find that there's a 10dB difference or more.

Wayne