That's correct in a perfect world, where the Summoner can just stand still and cast each DoT for 2.5 sec cast time without getting interrupted. Also keep in mind the first DoT tick usually does not go off due to the global tick timer and factor in all the other delays the damage reduces considerably.
DoTs tick every 3 seconds pretty much, in that amount of time a bard can shoot for just as much damage, with your crits youd be dealing even more.