That’s the general case with decent dual subs, however the 9060 towers may extend low. I would try it both ways to see what sounds best. It doesn’t cost anything to play around with it. If the 9060 towers participate to their ability and roll off clean there’s something to work with. Having a couple more sources of “mid bass” might help. Easy to tell which is better by loading up an action movie scene with lots of explosions.
It certainly never hurts to try, and after looking at he 9060 and seeing he FR on their powered woofer (which is pretty close to a 10" sub),it is a much better candidate for running full range than many speakers!
As you can see above, the 9060 is down at least 10dB by 200Hz (which is a reasonable top end for a typical subwoofer) except for the case of the minimum (green) setting.
For many full range speakers, the woofers are asked to play into higher frequencies. For an extreme example, the Klipsch RP-280F has dual 8" woofers which play down to 37Hz at -3dB (measured by Brent Butterworth); however, they are crossed over to the horns somewhere around 1700Hz.
I hope someone who knows about the mechanics of speakers, like
@TLS Guy or
@Dennis Murphy will correct me if I am mistaken, but I believe attempting to play cleanly at 1700Hz while pushing xmax excursions at 37Hz is asking a lot of a driver. Admittedly, this is an extreme example, being a two way speaker, however 3-ways reasonably play up to the 500Hz-800Hz ballpark and in such a case, it seems beneficial to let a subwoofer do the heavy hitting down low.