I think that sounds correct..once you setup your receiver correctly and adjust your crossovers, etc... you most likely will have an 80hz or so for the 150 anyway, so most bass from that channel will slope to the sub.
I would assume the newer speakers all have similar drivers V4 I believe now, at least in the standard line. I've never owned Polk, so can't really comment on that brand. I've always considered them a retail type brand you see in stores, versus direct from mft like Paradigm, Axiom, etc...
Looking forward to your results..
