Note 1 at Acts 22:25: It is very interesting to note that Paul used his Roman citizenship to stop the Romans from beating him (see note 2 at Acts 16:37, p. 673). This is the opposite of what he did in Philippi (see note 3 at Acts 16:37, p. 673). It is possible that he simply didn't want another beating so he demanded his rights or perhaps this was the leading of the Lord that eventually gave him an all expense paid trip to Rome (Acts 25:10-12).

Regardless of Paul's reasons, Paul did wait until he had been bound before he mentioned his Roman citizenship thereby still gaining the advantage of causing the chief captain to fear (v. 29) and yet averting another beating.