So to my point above, there is no BV attached to having AM ability in base BV calculations?
There is a BV attached to AM ability, Sartris was either wrong or misspoke, or was talking about something else.
All infantry that can make AM attacks (determined by type, and if battler armor of the right types have the hands for it), pays extra in the offensive weapons section for AM ability. Now, if you are foot infantry that are not antimech trained/equipped, you can still make AM attacks, and still pay BV for it, but are treated as skill 8 (and thus get a discount, for being 'bad' or unequipped to make AM attacks). For a foot rifle platoon, adjusting for speed factor, they spend 24 BV on AM equipment, and get a .85 multiplier for pilot skill 8 (which is a 13 point discount). So 'net' their AM attack costs them 11 BV in the 77 BV you pay for them.
If you take infantry that lack AM, like Sartris mentioned, then you are taking something like mechanized infantry. Mechanized infantry DO NOT pay for AM ability in the weapons section of the BV calculation, so in techmanual you must put them to skill 5, and can not ever change that antimech skill to get a discount or to pay extra for the skill, because mechanized infantry are not able to make AM attacks. So because you are not allowed to change their AM skill, you cant be overcharged.
Battle armor DO still have an AM skill (it is not set to 5 even if they do not have the ability to make AM attacks). Battle armor that lack AM attack ability do not pay anything for AM attacks (like mechanized infantry). However, Battlearmor DO use the AM skill, even in total warfare, for things outside of AM attacks. Its edge case stuff, but you can have/pay for AM skill 1 assault BA without being able to make AM attacks, if you really like climbing/jumping through buildings.
EDIT: I will mention as a PS, the BV costs for infantry are garbage--as in they are bad and not at all in line with every other unit or the infantries honest abilities. Infantry drastically underpay for everything in their formula, like treating their 'bubbles/health' as structure that can be crit in the formula but not taking crits, not paying for damage reduction like reflective armor does, not paying for their bonus mobility/facing, not paying for no move mod, not paying for infinite ammo, ect ect, with the arguable exception of AM attack ability on post damage errata weapons. So while I dont think Mauser IIC infantry should pay as much as they do for their AM attack post damage Errata, the rest of their costs are all so stupidly wrong that I have no sympathy for them with their 148 BV AM attack with Errata reduced damage versus the 24 BV AM/swarm attack of a base rifle squad because the entire infantry BV formula needs an errata to correct pretty much every single calculation in it. Also, Mausers/all the dual guns are dumb, and the conversion formula that created them and counts you shooting 2 guns at the same time to give them that silly damage value needs to be scrapped. Rant over LOL.