What is the AF and ABS of the test dummy? The resist are set @ 26%, but in order to calculate the expected dmg done, you must also know what the AF and ABS of the target are?
IIRC its 145 AF, no Absorb, no damage type tolerance. I had a thread a couple weeks back where the devs gave the info here.
After that thread, I simply made a calculator in google sheets that was accurate to a few %. Phoenix uses these formulae with the sole exception of the AF calculation is 45/50 * DefenderLevel instead of 20.
(And yes, that is a significant change in damage output, but I can't find my logs from 2003 to compare for argument)