Jim,
I am at a loss too but there are many possibilities for the discrepancy. If Craig measured his acculines as having higher sensitivity, and they were both positioned in the exact same position. then either his pair of acculines are different than my pair or his pair of 340 SE are out-of-spec, or there is a fundamental difference in how the sensitivity measurement is being performed.
One thing that bothers me about Craig's response measurements is that with at least the one 340 SE that he measured (no attenuation, no screen), the tweeter level is down about 5dB on average compared to the 2k - 3k region. This could be due to measuring equipment (I am not a fan of Sound Card based measuring systems, too susceptible to noise) and many microphones roll-off highs. The tweeter level of the 340SE should be slightly higher than the upper mids, not lower. Craig purchased the recerts a few months ago, I am going to look up the response curves in our database this evening.
Also, I appreciate the kind words