what the heck are my Communion Slaves doing?

[Zooko]

I just watched a battle and painstakingly transcribed every spell cast by my mages, and what their fatigue was after each turn. I have several questions:

1. Why did the Communion Slaves not cast any spells?
2. Why did the Communion Master go out of script on turn 5?
3. Why did a couple of the slaves change their minds and cast a couple of spells at the end of the battle (turn 18).
4. Why does the fatigue get distributed unevenly?
5. Why does the fatigue get distributed differently when the Communion Master casts a spell on one turn than when he casts the same spell on the next turn (turns 6 & 7, turns 9 & 10 & 11, turns 14 & 15, turns 16 & 17)?
6. Why does the Communion Master cast worse spells like Banishment or Solar Rays instead of better spells like Holy Pyre?
7. Why do my mages sometimes recover as much as 8 fatigue per turn? (4 is due to Summon Earthpower)

Here was the script:

Enforca: Communion Master, Power of the Spheres, Summon Earthpower, Phoenix Power, Immolation, spells
Metase: Communion Slave, Body Ethereal, Luck, Rage, Blink, spells
Clarbune: Communion Slave, Luck, Body Ethereal, Curse of the Stones, Blink, spells
Bphlah: Communion Slave, Body Ethereal, Luck, Rage, Blink, spells

Actual behavior: Enforca cast 1. Communion Master, 2. Power of the Spheres, 3. Summon Earthpower, 4. Phoenix Power, 5. Summon Fire Elemental, 6. Banishment, 7. Banishment, 8. Luck, 9. Banishment, 10. Banishment, 11. Banishment, 12. Iron Will, 13. Holy Pyre, 14. Solar Rays, 15. Solar Rays, 16. Body Ethereal, 17. Body Ethereal, 18. none, 19. Luck

The other mages cast Communion Slave, then did nothing until turn 18 (the same turn that Enforca did nothing) when Metase cast Body Ethereal and Bplhah cast Mind Burn.

Here are the fatigue levels of each mage after each turn. The fatigue caused by my opponent's Rigor Mortis is included in parenthesis, when applicable.

 turn

   |   mage ->

   v      Enforce      Metase     Clarbune    Bphlah

   1         19          19          19           3

   2         31          41          52           9

   3         37 (37)     69 (77)     58 (70)     33 (29) ???

   4         41 (50)     79 (75)     74 (70)     31 (41)

   5         69 (70)     84 (80)     89 (85)     50 (54)

   6         72          82          87          62

   7         68          78          83          58

   8         72          82          87          60

   9         80          89         107          64

  10         78          87         100          68

  11         86         100         104          72

  12         86         112          99          84

  13         85         104          98          84

  14         85          99          98          79

  15         86          99         109          77

  16         87         102         119          75

  17         88         103         115          73

  18          ?         118           ?          72

  19         98         113         101          70

One theory as to why Enforca didn't cast Immolation is that he didn't want to hurt the three White Knight bodyguards. Another is that he thought casting Immolation would hurt the Communion Slaves, not realizing that they had fire immunity fro.... Oh. I see that they only had 50% resistance from Phoenix Power. Maybe next time I'll do Phoenix Power, Fire Resistance, Immolation. So I guess the explanation to question #2 is Enforca was smarter than I was and knew not to cast Immolation.