According to 'Revelation - Its Grand Climax At Hand', published by The Watchtower and Bible Tract Society, from the 2006 revision of the original 1988 published book, studied and believed to be "the truth" by Jehovah's Witnesses worldwide, angelic trumpet blasts and their prophetic significance is as follows:
Revelation 8:7
1st Angel Trumpet blown = September 10, 1922 convention in Cedar Point, Ohio.
[Page 134, paragraph 18]
Revelation 8:8, 9
2nd Angel Trumpet blown = August 18-26, 1923 convention in Los Angeles, California.
[Page 134, paragraph 22]
Revelation 8:10, 11
3rd Angel Trumpet blown = July 20-27, 1924 convention in Columbus, Ohio.
[Page 137, paragraph 33]
Revelation 8:12
4th Angel Trumpet blown = August 29, 1925 convention in Indianapolis, Indiana.
[Page 140, paragraph 39]
Revelation 9:1
5th Angel Trumpet blown = September 1-8, 1919 convention in Cedar Point, Ohio.
[Page 143, paragraph 5]
Additionally, led to emphasis of some judgments which brought "first woe" during May 25-31, 1926 convention in London, England.
[Page 147, paragraph 18]
Revelation 9:13, 14
6th Angel Trumpet blown = 1919 release from bondage.
[Page 149, paragraph 4]
Additionally, led to emphasis of some resolutions which brought "second woe" during July 24, 1927 convention in Ontario, Canada.
[Page 149, paragraph 5]
Revelation 11:15
7th Angel Trumpet blown = 1914 when Jehovah enthrones Jesus.
[Page 171, paragraph 2]
Additionally, led to "third woe" highlights at July 30 - August 6, 1928 convention in Detroit, Michigan.
[Page 172, paragraph 5]
Conclusively then, if the above is "the truth", it appears Jesus and John got their angelic trumpeting sequence of events out of order towards the end of the blasts. Nonetheless, it all aligned to advertise some conventions of a group of bible students who would later take on the name of "Jehovah's Witnesses".
The name of those bible students was picked by the second president of the company, J.F. Rutherford, who believed and preached the prophets of old would rise from the grave in 1925 and live in a mansion he had built for them. Meanwhile, he lived in that mansion - calling it Beth Sarim, located in San Diego, California. Furthermore, he purchased a big fancy automobile to drive the prophets around in after they rose from the dead, but used it for himself in the meantime.
Think about it. Supposedly, prophetic trumpet blasts written about thousands of years ago in which is arguably the most sacred and highly revered book of all time by many - The Holy Bible - were blown out of order by angels, but ultimately performed to announce convention events of a publishing company whose president and spiritual leader was involved with and preached about what is mentioned in the previous paragraph.
This is official doctrine, teaching, and beliefs of Jehovah's Witnesses.