For the gateway requirement can a 3% safe harbor non elective contribution be used to offset the 5% necessary allocation?

We have a new comparability plan and I wanted to see if we can offset the cost of the gateway requirement with the 3% safe harbor non elective or if we have to give an addition 5% on top of that? Can we also offset it by a safe harbor match or no? 

Obviously this is all assuming that the 5% is lower then the 1/3 of the highest contribution to HCE's.