Two expensive and nominally identical drivers should not differ that much in DCR. On a typical amp, the driver with the lower resistance should play louder than the other.
To test this out, you could play them face to face with a mono signal with one in reverse polarity and a rheostat or 1 ohm resistor in series with the driver with lower resistance.
You should get a high degree of cancellation if the drivers are identical in sensitivity, and you might find you need to add about an ohm of resistance to achieve that.
If that is the case, I think this is grounds for money back, or at least replacement of the out-of-spec driver.
Experimentally short across the resistor or potentiometer to hear the degree of mis-match.