Like I said in my edit up above: The only way the table entry, using the allocated space, cannot disagree with the text entry is if they replaced it with "See text."
However, if you treat the table as a list of weapon price modifiers, with the weapon cost being the base price and the modified weapon cost being the final price, the smartgun entry makes sense as written; it is modifying the number at the beginning of the equation. As such, the equation would look like this:
Weapon cost x base price modifiers + (weapon mod price x rating) = modified weapon cost
where rating = 1 if weapon mod price does not include a rating factor
Smartguns then go in the base price modifiers. Thus, a weapon costing 1000 nuyen with an internal smartgun and a gas vent 2 would look like this:
1000 x 2 + (200 x 2) = 2400