Those curves say that if you are going to listen at "sane" levels, stick with the standard.

If you want to listen at insane levels, you need to ask Axiom for a different set of curves. You need the curves for 105 dB and above. Those curves will likely show that the standard driver compresses while the HP driver keeps on going.

My advice continues to be go with the standard and save your money for a sub in the future. Even better, use the funds for room treatments.

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