In MoP, Explosive Shot ticks are going to work more like how Piercing Shots works: if you apply another Explosive Shot while an existing Explosive Shot DoT is on the target, the game will add an extra tick like it does now, but then it will add the total DoT damage of the new shot to whatever remains of the old shot, and then divide that entire number by 3 (the number of ticks with the one extra added) and that will be the new damage per tick.
Thus no damage is ever lost: (Total damage of new DoT + Total damage left undone from old dot) / (# of ticks + 1) = damage per tick
Let’s take a look at an example to illustrate. Let’s say for the sake of easy numbers that our Explosive Shot hits for 100 damage, and then ticks every second for the next two seconds for another 100 damage per tick. Thus our numbers look like this:
0:00: shot lands for 100 damage
0:01: tick for 100 damage
0:02: tick for 100 damage
Thus we fire Explosive Shot and we do 300 damage total. Now let’s say Lock & Load procs, and gives us the ability to fire three Explosive Shots in a row. This is what would happen:
0:00: shot lands for 100 damage
0:01: tick for 100 damage and 2nd shot lands for 100 damage.
– RECALCULATION: There is one tick left for 100 damage from the first shot, and two ticks for 100 damage each for the second shot. Add it all together for 300 damage; add one tick for 3 ticks. Divide 300 dmg by 3 ticks and we now have 3 ticks to go for 100 damage each.
0:02: tick for 100 damage and 3rd shot lands for 100 damage
– RECALCULATION: There are two ticks left for 100 damage each from the last recalc, and two ticks for 100 damage each from the third shot. Add it all together for 400 damage, add back to 3 ticks. Divide 400 dmg by 3 ticks and we’ll now have 3 ticks for 133.33 damage each.
0:03: tick for 133.33 damage
0:04: tick for 133.33 damage
0:05: tick for 133.34 damage
Thus we did a total of 900 damage with three Explosive Shots. 300 damage for one, 900 for three — this way even spamming the shot we will never, ever clip a tick. Note that you’ll also never have more than 1 extra tick on your DoT.
http://www.warcrafthuntersunion.com/2012/06/explosive-shot-in-mop-cannot-be-clipped/