It was what it was. During speaker calibration the MT110s came back 2db less than the RF62IIs. Same distance, same tweeter height etc... I found that speaker sensitivity (which is what is measured) is different than in room efficiency. The RFs are ported with larger cabinets leading to greater overall in room efficiency. My Q750s are 4db less efficient than the RFs. Smaller cabinet, no horn, and passive radiators. Makes sense to me. YMMV.@Kini62, I see now that your experience with the MT110 is fully documented in the PSA thread. To briefly sum it up you said you were disappointed to find your MT110s to be less sensitive than your Klipsch RF62IIs the way you were running them in your room when you fully expected the PSA to be more sensitive than the Klipsch. This result was so unusual that many MT110 owners, including some who had switched from Klipsch, tried to help you identify the unique issue you had run into. You said you were so disappointed that you would return the MT110s if the shipping cost from Hawaii wasn't so high.
@Tom Vodhanel also tried to help you work through your issue and then generously offered to pick up any additional cost of shipping the speakers back to the mainland. You eventually took him up on that offer and expressed your gratitude to Tom and the whole PSA community for all the time and effort they put into trying to help you through a speaker sensitivity issue that no other PSA owner said they had experienced.
In conclusion it seems your experience with lower than expected MT110 speaker sensitivity was unique to the PSA community and would most likely not be applicable to others. We can only hope that someone like @bikinpunk will find a way to get hold of an MT110 or other PSA speaker, run it through his Klippel measuring device and share objective measurements of the performance including actual sensitivity so we don't have to rely exclusively on user listening impressions.