difference between excitation port phase angle and integration line direction

In HFSS, what's the difference between the excitation port offset phase under Edit Sources and the direction of integration line we draw for a lumped source?

Say I have two sources with opposite integration lines, would this be like having one source with one offset phase equal to 0 degree and the other equal to 180 degrees?

I really need to understand the purpose of integration line and its direction as HFSS documentation is mediocre to say the least.

Thanks.