Dispensationalists insist on taking the number 144,000 literally, but they do not take their description literally. Such inconsistency is glaring. But Jenkins and LaHaye substitute the cross for this and do not limit it to their 144,000 Jewish evangelists. For example, John introduces the 144,000 saints in Revelation 7 and does not mention the two witnesses until chapter eleven. They are in heaven, not on the earth.
Every false doctrine is plagued with such inconsistency and contradictions.
As for the first four trumpet judgments in Revelation 8, these likely symbolize the natural disasters which God used to punish Rome. Furthermore, he leaves out the tribes of Dan and Ephraim. 12,000 Israelites are chosen from each of the twelve tribes which equals 144,000 when multiplied out. In Revelation, the number 12 represents the people of God and the number 1000 represents completion. Thus, the number 144,000 simply represents all of the saved.