I dont think it's 84ish. I think it's more like 87ish vs. 91sh. I'm not sure I trust the chamber Soundstage measurements for the M5. The ferrofluid in the tweeters may have been cold. When I bought them, I went by what the reviewer, Andrew and Craig told me and discarded the measurements.

House of the Rising Sone
Out in the mid or far field
Dedicated mid-woofers are over-rated