Math of condi dmg not coming out right - Possible bug?

So I"m changing out all of my ranger gear for new gear for a new build. While I'm doing this, I'm calculating all of my condition damage values to see how my skills will be affected with different gear stats. I'm looking at the numbers of the same skill in 3 different ways (expected, game tool tip, and actual) and NONE of them match up. I'm hoping somebody can tell me why. I'm noticing these discrepancies ONLY with pulsing skills such as Revenant's Searing Fissure and Ranger's Viper's Nest. What is the game actually doing with these skills that the math isn't?

"Expected:" Before doing anything, I calculated what the damage should be with these skills based on my condition damage and duration."Game Tool Tip:" The damage the game expects the skill to do. The damage listed for the condition on the skill fact."Actual:" How much damage the skill actually does.

1. Condition Dmg = 0; Condition Dur = 0%; no sigils, runes, traits, or boonsFlame trap: pulses 4 times; 1 stack burning for 2.5s per pulseExpected: 1310 (131 2.5 4)Game Tool Tip: 1312 (328 * 4)Actual: 1320

2. Condition Dmg = 1370; Condition Dur = 0%; no sigils, traits, or boonsFlame trap: pulses 4 times; 1 stack burning for 2.5s per pulseExpected: 3441 (344.13 2.5 4)Game Tool Tip: 3444 (861 * 4)Actual: 3468

3. Condition Dmg = 1050; Condition Dur = 37.33%; trap duration +60% (trait), no sigils or boonsFlame trap: pulses 4 times; 1 stack burning for 5.49s per pulse (2.5 1.6 1.3733) - tool tip displays 5.75s instead of the expected 5.5sExpected: 6451 (293.75 5.49 4)Game Tool Tip: 7316 (1829 *4)Actual: 7344

I had similar results with Viper's Nest and Searing Fissure, but not with Ranger's Crossfire or Poison Volley or Firebrand's Chapter 1: Searing Spell. It seems that this only occurs with pulsing skills. As you can see, they deal more damage than expected. I doubt this is a bug or it would have been caught long ago, so I expect that I am missing something in my math. Can somebody please help me understand what is really going on here?

I haven't done game math in awhile, but I'm pretty sure it is rounding. The way the game works is, there's a tick refresh rate that determines how fast consecutive processes can be handled. It is the innate refresh rate of the game itself. However, a lot of actions are executed out of sink with the refresh rate itself. In particular, when it comes to fractions of seconds with conditions and delayed applications. Though the game's action counter refreshes every 1/20th of a second or so, the animation and skill effects of attacks carry through smoothly at a much faster rate, thus causing the actions to land out of sync. Any discrepancy between duration game refresh rate is handled by rounding up the duration. This causes a very small portion of additional damage to be attached on to the end of a conditon's normal run.

At least I think that's what is happening... If it isn't the refresh rate, then it is probably the game's tooltip lying about the exact duration of a skill, for the sake of convenience. I've seen it happen, too. I'd notice randomly while fighting on my condi classes that I'd get small ticks of damage on top of my regular attacks. Often its an additional condi tick below 10 points of damage, just comes out of nowhere.

Chances are, the only person who can answer this question with some certainty is a developer.