This is my understanding.
When contention occurs NIOC Scheduler is sending network IO to the NIC queue based on shares. So it depends on current traffic.
Let's assume your NIOC settings:
FT 10
Management 30
Virtual Machine 40
vMotion 20
When there is only FT and vMotion traffic and nothing else saturating 10Gb then FT will be able to get 3.33Gb (33%) and vMotion 6.66Gb (66%) because 10 and 20 shares are fighting for 10Gb (100%).
If another traffic type will be participating in total network traffic then ratio will be recalculated based on shares. It is all about scheduling and IO prioritization into NIC queue.
So I think that when you don't use iSCSI, NFS, and Replication traffic types it will not affect ratio of active traffic types.
However I would set not used traffic types to 0 because it can potentially eliminate traffic types which are not expected anyway.
Just my $0.02.