(Answered) How exactly does TAG work with Indirect fire

[TannTalas]

My question is this explanation correct?..................

In Alpha Strike, Target Acquisition Gear (TAG) and NARC Missile Beacon are both special abilities that allow a unit to guide indirect fire weapons such as artillery and missiles to the target. However, they differ in their functionality 1:

TAG is a laser designator that must be kept on the target to be effective. It functions for LRM, SRM, and Arrow IV artillery. When you paint a target in range, you can improve the hit modifier when firing indirectly (canceling out the indirect fire modifier; p. 47), and you may use copperhead homing rounds (p. 144).

NARC Missile Beacon is a beacon that attaches itself to the target, thus removing the requirement to keep someone pointing a laser at the target. It only works with LRM and some SRM systems. When you paint a target in range, you can use semi-guided missiles to apply one of two possible bonuses (extra damage or easier to hit modifier; p. 150). Additionally, it acts like Artemis for missile launchers and gives a unit with NARC guided ammo a +2 to cluster rolls.

[nckestrel]

TAG has many different options.
https://bg.battletech.com/forums/index.php/topic,82971.0.html
Runs through all of the options for TAG.  "Painting" and "successfully designating" are specific rules terms.  As rules, TAG doesn't always have to paint (see the link). Lore wise, yes, TAG "paints" the target.  Rules-wise, sometimes TAG requires the specific painting/successfully designating rules and sometimes it does not (see link above).
TAG can spot for any indirect attack (IF or artillery, p90, newly added to 6th printing), and can give a target number modifier for indirect artillery attacks (p47).  It can also work with the semi-guided LRM (p150) and homing arrow IV (p152) optional rules.

NARC does not require indirect fire.  It works with LRM, SRM or IF units (p87), whether direct or indirect.
Once a target is hit with NARC, any unit that attacks the NARCed target, and has the LRM, SRM or IF specials, does additional damage (p87). There is no target number modifier for attacks on NARCed targets.
NARC has no relation with semi-guided missiles.  Semi-guided LRMs are a specific type of missile that works with TAG (see above), not with NARC.  Lore wise, there are specific NARC guided munitions.  Alpha Strike assumes if you have a unit with NARC, that your other units have munitions that can work with the NARC. So there's no NARC-guided munition rules in Alpha Strike.

Additionally, it acts like Artemis for missile launchers and gives a unit with NARC guided ammo a +2 to cluster rolls.

There are no cluster rolls in Alpha Strike.

[TannTalas]

Ok thank you, but just to be sure as my friend is quite stubborn, here is the argument.
 
Dasher-A w/TAG moves up and with a successful attack roll TAG's a Warhammer.

A Bane with an IF7 is parked behind a level 3 hill and out of sight. Normally the Bane would apply an indirect fire modifier of +1 to its to hit roll for firing indirectly. However, thanks to the TAG canceling out the indirect fire modifier it no longer adds that +1 to its attack roll. The Bane has not moved, as such standing still when firing, so it gains a -1 to it's to hit roll. So a normal target number of say 9 (8, +1 Indirect fire modifier) becomes a 7 (- 1 for standing still, -1 for TAG cancelled Indirect fire modifier) all without using special ammo like semi-guided or homing. Is this correct?

[nckestrel]

TAG has no effect on standard indirect fire (non-artillery).

[TannTalas]

So bottom line.... TAG only works with Semi-Guided and homing ammo and gives no pluses or minuses to the indirect fire modifier of the IF unit's attack.

[nckestrel]

It's primary use in Alpha Strike is to improve indirect fire from artillery.  If the spotter has TAG (and is within range, etc) and is spotting for an indirect _artillery_ attack, there's a -1 target movement modifier.
Homing artillery and semi-guided LRMs are optional rules that TAG is also important for.