OA, page 33-34
"Character who have levels of only monk classes always get more unarmed attacks than they would noramlly get based on their base attack bonus (additionaly attacks at intervals of -3, instead of -5). Characters who have levels in other classes as well may or may not gain an advantage from this, and any advantage is often slight.
"Table 3-1: Multiple Unarmed Attacks
Base Attack Bonus Additional Unarmed Attacks
+0 .... ---
+1 .... ---
+2 .... ---
+3 .... ---
+4 .... +1
+5 .... +2
+6 .... +3
+7 .... +4/+1
+8 .... +5/+2
+9 .... +6/+3
+10 ... +7/+4/+1
+11 ... +8/+5/+2
+12 ... +9/+6/+3
+13 ... +10/+7/+4/+1
+14 ... +11/+8/+5/+2
+15 ... +12/+9/+6/+3
"Example: Asako Turima is a 10th-level monk/4th-level henshin mystic. His base attack bonus is +10 (+7 from his monk levels, +3 from his henshin mystic levels). Normally, this would give him an additional attack at +5. He can instead take the additional unarmed attacks listed for his +10 attack bonus (since the entire bonus is derived from monk and mystic levels) on Table 3-1: Multiple Unarmed Attacks, +7/+4/+1. Thus, he can make four attacks in a round with an unarmed strike (or a monk weaopn), at +10, +7, +4 and +1. When using another weapon, he can make two attacks at +10 and +5. He has the unarmed damage, AC bonus and speed of a 14th-level monk.
"Togashi Tidaiko, however, is a 3rd-level samurai/5th-level monk/ 7th-level tattooed monk. Her base attack bonus is +11 (+3 from her samurai levels, +3 from her monk levels, and +5 from her tattooed monk levels). Normally she would have two additional attacks at +6 and +1. She can instead take the additional unarmed attacks listed for a +8 base attack bonus from her monk and tattooed monk levels on Table 3-1, +5 and +2. She makes three attacks in a round, whether armed or unarmed. If unarmed (or using a monk weapon), she can choose whether to strike at +11/+6/+1 or at +11/+5/+2. Armed with an ordinary weapon, she must attack at +11/+6/+1. She has the unarmed damage, AC bonus, and abase speed of a 12-th level monk."