I would like to echo grienne54's sentiment, with a little more detail, that not all towers work the same and their placement is also a factor. A Huntress Explosive Trap for one activation is an Area of Effect (AOE) trap hitting many targets, but the placement of that trap is also significant. Further up a lane, away from blockades, the trap takes a single shot at each group that passes over it. Yet when an explosive trap is placed directly in front of a blockade it may have multiple activations on a single group, and when those grouped are bunched in front of a blockade each charge may yield hits on more targets. Alternatively, the standard Squire Cannonball Tower hits one target at a time but does so rapidly. This sort of tower is seldom placed anywhere other than a position where it can strike repeatedly. Then, and this is where it gets a bit more complicated, an Apprentice Frostbite Tower which slows multiple targets with an AOE subjects those targets to more possible attacks when passing through a trapped area. And of course there are differences in whether a tower/trap/aura can hit ground targets, air targets or both. This is not to dismiss the original poster, who has done great work highlighting the difference in DPS to DU value, only to state that the DPS value does not tell the whole story.