NCO with Cyclone V

I don't yet understand the exact problem. I can imagine that you want to enforce DSP multiplier style because you fear to run out of LEs or to improve design timing. My expectation is however that Quartus will just do this in a design where multiplier style matters.

Up to now, my multiplier style synthesis attributes on an entity level have been observed by Quartus. I didn't yet try with Cyclone V, but I don't see an indication why I should expect different behaviour. In any case I don't think that the problem is specific to NCO.