Yeah, I'm not sure how to handle profiles with Heavy Carapace already added, but it definitely makes sense to me to reduce Initiative at all times when adding it to a 'normal' fighter.
Reducing initiative on a charge doesn't make much of an effect, really.
The Initiative and movement penalty is applied when the fighter charges. The rule states "the fighter's Initiative is reduced by -1 and their movement by 1" when making a Charge action".
There is no comma between the " -1" and the "and" so each part of the sentence is in the same clause which ties the penalties to the Charge action.
If the rule had the Initiative and movement penalties in different clauses or sentences then it would be different.
Charge someone near a ledge and initiative becomes much more important. Or on top a vehicle.
You could also have a opponent then lob or shoot a Photon Flash grenade at you. With the penalty you are much more vulnerable to being Blind. (You still count as Charging for the rest of the turn even after your activation ends).
As all save rolls are triggered when "if a hit results in a successful Wound roll, or leads to a injury roll" (Core p.124) and the Flash trait states no wound roll is made (it is not in place of the wound roll) the Flash weapon ignores your shiny 3+ save.
A immobile combat fighter is useless. They may have crushed a sacrificial jive in the charge but can now lose next turns activation, thus can not move or at least drop prone to avoid incoming fire as they will be standing up from the melee, and can only make Reaction attacks hit on a 6. A blind fighter also can not turn to face either In melee so attacks outside the vision arc (you need to be a activated fighter to do so). That misses out on your 3+ save. A power knife attack from the side or rear suddenly becomes a S+2 AP-2 Power strike so potentially damage 2. Assuming S3 base that's a S5 hit with only a potential save of 6+. And you cannot really hit back. For 25 credits.
I've seen a heavy carapace monster be blinded and immobile for 6 consecutive turns after a charge from one guy with a grenade launcher with flash grenades.
If they are Esher or nomad with a 3+ Initiative just add a cheap concussion weapon (a trait that also ignores the armour save) and you virtually guarantee the Heavy Carapace armour combat monster is out of play for a entire game.
Flash grenade your heavy Carapace opponents.
) to the melee/sidearm bit - on the "in addition to any other weapon carried". Or at least that sticks out. 
