Generally, numbers like that are used as Bonus Modifiers - they add to the bonus the attribute/skill normally grants - and not the actual number. Example: Brokk, the high man (+10 stat bonus) fighter has a 100 Strength (+25 stat bonus), for a total of +35 Strength stat modifier. If they get a +15 bonus modifier for Strength, it will be added to the +35 for a total Strength modifier of +50.