Okay I've had a fiddle with some stats but it's kind of tricky with the children off school for Christmas!
First of all let's look at some facts and assume that Joe is always right (might sound stupid but what it means is whatever system we come up with mustn't contradict what is already written, toooo much). There may be more examples than this - just a quick flick!
Lone Wolf/Grand Master Allies:
Horse (only with Animal Control, assume Bk13+ already accounted for)
+1CS Bk6/164 (This seems to be an exception/not enough time to work properly?).
+2CS Bk8/88, 106, 162, Bk9/85, 244, Bk10/118. Seems a standard, consistent bonus.
Kasin Bk7/290 Double Damage vs Beastman Gaoler.
Paido +5CS Bk8/41, 159 Half Damage vs Kezoor.
Sogh "Impressed" +2CS Bk9/238, 309.
Sebb Jarel Bk10/172 Half Damage vs Gorodon.
Karvas +5CS Bk23/10, 34, 103, 159, 284, 301.
Troopers/Yeng +1CS (each) Bk 28/63, 82, 106, 115, 179, 224.
Enemy Alliances (where we know the ONLY difference between CS/EP is number of enemy allies/all other factors unchanged):
Bk6/299-282 (2) Backstabbers CS 18 EP 25
Bk6/299-114 Backstabber CS 15 EP 22.
So the second Backstabber makes an improvement of +3CS/+3EP.
Bk10/8-251(or 8-131-251) (5/6) Zagganozod CS 24 EP 35.
Bk10/8-131-344 (3) Zagganozod CS 20 EP 32.
So 2/3 extra Zagganozod make an improvement of +4CS/+3EP.
Bk13/148-38 (3) Ruel Giganite CS 50 EP 80.
Bk13/148-80 (2) Ruel Giganite CS 38 EP 60.
Wow that extra Giganite makes +12CS/+20EP!
Bk13/177-86 Acolytes of Vashna CS 36 EP 50.
Bk13/177-137/345 Acolyte of Vashna CS 25 EP 40.
The extra Acolyte makes a difference of +11CS/+10EP but what effect does the Medallion of Protection have?
Hmmm. So it seems a wide variety of results, with only a vague pattern. Almost certainly Joe doesn't have a magic formula, rather a few comman sense assumptions - 'helpful', 'very helpful', 'extremely helpful', etc. Looking again at the stats what seems to jump out at me is the quality of the assistance; the more the ally appears to trust or care about their fellows or be able to work with them, the better the bonus apears (this might explain why giaks in Bk1 rarely change by more than 1 or 2 CS depending on how many you fight.
(PC's)
Pick the best applicable description to the current situation. Pick a random no. Odd use result before the oblique, even after. (Odd/Even):
+0/+1CS Disorganised Rabble/"Oi! Give us a hand!"/"I'm only in it for the money." Standard bonus, no time for any strategy, everyone fighting independently together, unsure of each others reactions to different situations.
+2/+3CS Trickster Comrades/"Just stick to the plan this time. If you fall back here, I'll come in from the side here..."/"Alright I'll do it but you owe me! No, Duadon doesn't count." A few tricks up each others sleeves, work well together, quite confident of the situation, will take a few risks to improve strengths/reduce weaknesses, provides very suitable spell/ability/equipment support.
+4CS/+5CS Bloodbrother Tacticians/"Let us face destiny side by side"/"I owe you my life". Unquestioning confidence in each other, almost instinctive knowledge of optimum tactics for any situation, risk life to maximise strengths/minimise weaknesss of fellows, provides perfect spell/ability/equipment support.
Alternatively when outnumbering a single foe you may inflict/receive +1EP/-1EP if CS bonus would be +2/+3 and inflict/receive double damage/half damage if CS bonus would be +4/+5.
NPC's.
As above but each +1CS = +10%CS & +10%EP, added seperately for each ally. In other words if an opponent has CS20 EP30 and the bonus is +20%, if they have three allies it is CS32 EP48 (+4CS+4CS+4CS and +6EP+6EP+6EP) - not CS24 EP36 (+20%CS/EP).
