Boosting a frequency with an EQ isn't going to boost it if it's not there... If you add a boost from 380-460hz, it's going to boost the harmonic content in that range that actually exists in the sound you are trying to boost.
If you have a sinewave at 440hz and boost the shit out of 1k, it is going to sound exactly the same as it did with the EQ off because there is nothing at 1k to boost. The EQ isn't adding any new frequencies to the signal, only changing the levels of the frequencies that are already there. So it doesn't matter at all what specific frequency you are boosting because any boosts are going to be wide enough to encompass where that general frequency actually is in your signal.
You cannot create dissonance with an EQ, you are worried about something that isn't real. Again, boosting 441hz on a 440hz sinewave will not create dissonance. It will boost nothing because 441hz isn't even there to boost. 10 times 0 is still 0.