Does the BP increase causing the damage to increase, or is the game coded to just increase the damage output by 33.3%
After a bit of research, I have found that Electo Drift and Collision Course are treated as Multipliers the same way STAB and Super Effective are. They get their own spot in the damage calculation equation, namely, the "other" spot. So to directly answer the question, it's more correct to say that it increases the damage they do.
Source
Hope I Helped.