I wouldn't worry about
what the manufacturer is saying in terms of length of time. Your doc is the best judge.
The manufacturer is just giving a guideline. A clinical trial showed that taking 6 mg Entocort for longer than 5 months is not likely to improve the chances of falling out of remission, so the manufacturer is probably using that as a guideline.
BUT my daughter did fine on modified SCD and just one pill Entocort for years, so each person is different. In fact, the only time she was hospitalized was when she tried to go completely off the Entocort in 2006.