^The 3.5's were sealed boxes. Keep in mind the slightly elevated impedance peak on the 3.5's occurs just about where the supplied bass booster eq comes in. So just where the extra drain on the power amp required from the bass eq comes in, it's offset by a higher impedance with it's correspondingly higher sensitivity. Though perhaps not evident at first glance, the subtle deviation from flat impedance at just the right frequency actually makes for a more linear load on the amplifier.
Perhaps the coincidental drivers; though they might have other positive attributes, might compromise linear impedance?
Perhaps the coincidental drivers; though they might have other positive attributes, might compromise linear impedance?