Here's Multiplicative(more realistic but still the real results would be between these two sets of numbers trending towards multiplicative the higher level we go)

Relevant Class lvl 5 Stuns- Chance to stun on median save(+0) Chance for a stun to perpetuate 1 time(2 rounds) Perp 2 rounds 3 rounds
Monk -------------------------5 -55.00%---------------------------------------- 0.00% ------------------------------------------------------0.00%---------- 0.00%
War Priest ------------------9 -55.00%---------------------------------------- 30.25% ------------------------------------------------------16.64%-------- 9.16%

----------------------------Max targets CC-able in one round Total average rounds of CC
Monk(continued)----------------------------3 ----------------------------------------1.5125
WarPriest(COntin)-------------------------2----------------------------------------- 9.99378
----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

Relevant Class lvl 11 Stuns Chance to stun on median save(+0) Chance for a stun to perpetuate 1 time(2 rounds) Perp 2 rounds 3 rounds
Monk -------------------------11 55.00%---------------------------------------- 0.00% --------------------------------------0.00%---------- 0.00%---------0.0%
War Priest ------------------16 55.00%---------------------------------------- 55.00% -----------------------------------30.25%-------- 16.64---------9.15

----------------------------Max targets CC-able in one round Total average rounds of CC
Monk(continued)----------------------------3 ----------------------------------------3.3275
WarPriest(COntin)--------------------------3------------------------------------------17.7664
----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

Even with the multiplicative numbers warpriest destroys because it doesn't have to make 2 accuracy checks against bad accuracy numbers. only one.