Does being host or having the host on your team matter? Halo4?

Sometimes I have to shoot someone with the dmr 6-8 times when they easily 5 shot me. Other times I easily 5 shot my opponent and I still have like 1/4 shields. How is this fluctuation possible some people I play with tell me it has to do with the host. I honestly don't know and it is incredibly frustrating. I love halo 4 like I am in love with it but due to this shots per kill issue I'm having my play is incredibly inconsistent. Has anyone experienced this? Oh and 9 times out of ten I have to spam the scattershot 5 times at point blank range and rarely get a kill only to face off against someone who picked up my scattershot and then one shots me from an absurd distance.