'Crappy Hour' -- Why I Hate Dynamis

This is something I've been noticing ever since I started Dynamis one-and-a-half years ago. For some inexplicable reason, I appear to experience a period during each Dynamis in which all my physical spells' potency and/or accuracy are diminished for reasons I can't explain. It seems to have nothing to do with mob-type or zone--it just seems to come in cycles.

I half-heartedly logged and tabulated my damage for Frenetic Rip during Dynamis - Bastok today. I was lazy, so I only include the first hour or so here. I chose Frenetic Rip because it's relatively more accurate than its other 2 counterparts, so I want to believe accuracy is not the general issue. Assuming 95% accuracy (which I'm sure I don't have, especially not in spellcasting gear), my highest chance of all 3 hits landing is .95^3 = 85.7%. I was not using food.

Likewise, because Frenetic Rip is a lower level spell, it should, in theory, have less damage variance than the other two. I omit outliers involving damage against pets and missed damage due to Perfect Dodge or Invincible. I did not omit spells under the effect of Chain Affinity, but rather assume Chain Affinity was randomly distributed among my observations. I further assume that all mobs, on average, are the same; a Vanguard Kusa that spawns at the beginning of Dynamis should, in principle, not be any weaker or stronger than one that spawns at the end, and on balance, though there is some variance among mobs due to class differences, these differences should cancel each other out. Here is what I find:

# Observations: 63 
Mean: 352 
Median: 358  
Range: 732
Standard Deviation: 145

Y-Axis is Damage Points 
X-Axis is numbered attempts (i.e. attempt #1, #7)

(Note the downward trend) >.>

For Dynamis - Bastok, one of the "easy" Dynamis zones, I find these data to be pitiful. For this hour or so, a full third of the Frenetic Rips I cast only did between 350 and 500 damage. Only about 15% of them exceeded 500 damage. A quick glance over the logs shows the other 2 didn't fare much better, though Disseverment, in general, had higher damage potential.

Maybe it was simply a facet of the fact that the Turtlebacks have higher defense than the other 2 Beastmen-races, but the downward trend remains, and it fails to explain why damage normalizes later on to a healthier 450-550 per cast.

I wonder if it's a bug involving physical Blue Magic specifically. Perhaps this is normal and other people experience the same ebb and flow of Weaponskill damage in Dynamis. I, for one, don't feel like I have this problem on THF. SA Mandalic Stabs seem to hit pretty consistently for 6-800 damage... And I never have this problem in other events like Limbus, Einherjar, ENM, etc...

Has anyone else noticed this?