Note that it may just be a feedhorn assembly, and probably don't have lnb's with it. That's all the Corotor II+ is, an assembly. Not seeing a picture, I can't confirm, so it could have them with it, but probably not. If it does, you're probably talking $300+ on cost, and that's if it has the cheapest possible lnb's. And, Dual Band is not the same as Dual lnb. It means it has both C-band and ku-band lnb capability.
As Tron said above, it should/will work better than the BSC621-2 C/ku lnbf. And it should also fit onto the 180cm dish. Although I don't have one, I would think so?