Combat Sensors & Multi-Plex Tracking

[WillyNilly]

I've searched the archives and couldn't find an answer to this question.

In MOO the equivalent to Combat Sensors only helped on direct fire weapons. They had no impact on Seekers (missiles). Is this true in SEIV or am I missing out on an advantage by not including combat sensors on ships that have only missiles as their offensive weapon? Fighters also have missiles, but they are classified as "direct fire weapons" so do those fighters need combat support or not?

The related question is on muli-Plex Tracking, which I understand is the ability for your ship to fire missiles and if the target is destroyed before all the missiles are gone then the missiles will chase a different target for their remaining movement points. If this is true then why do computer players put Multi-Plex Tracking on ships with only direct fire weapons? I must be missing something.

Any help would be greatly appreciated.