Question about Suboxone use??

My hubby is currently taking suboxone due to narcotic addiction. He has just started on this program and on the med bottle it states "no more than 12 mg max a day". I have just found out that he is taking around 20 mg. I have a call in to his doc but would appreciate some input on this. He has done rehab, methodone treatment, etc. This was his last chance with me and I am unsure if this is common (needing to take more than prescribed) or just another form of addiction. Thanks.

: http://alcoholdrugstreatment.info/question-about-suboxone-use