Not at all. Jesus' ascension is also his coronation. What had been a provincial body of believers of basically one nationality has gone beyond all borders to all nations. However, the tribulation is an ongoing reality of believers living in a fallen world awaiting the full consumation of Jesus and His church at His second advent. You might want to give a listen to the series of sermons Dr. Sinclair Ferguson gives on the book of Revelation, available at Sermon Audio. Where you might encounter some exegetical challenges comes in dealing with Romans 11 and what appears to be a future awakening among ethnic Jews through the work of Christ. I found Dr. John Murray to be helpful in his commentary on Romans. (I'm not saying that Roman 11 creates challenges for an amil position; I've experienced it as a difficult passage period.)