A Question about Timeline Changes
The question that you asked about Biblical Chronology is basically answered in The Times of the Judges.
You are correct. The extra time is located in Judges and the reason why is outlined in the above linked document. The extra 18 years were years that also appeared in Judges that most people forget about. It can be found specifically at Judges 10:8. The reason for the omission of this oppression by Ammon from other Biblical records may be found in the fact that it was the tribes on the east side of Jordan that were specifically mentioned in verse 8. However, verse 9 states that the Ammonites crossed over Jordan and severely distressed all of Israel so the extra 18 years must be added to the entire chronology, not just that of the tribes on the East of Jordan. For that reason, the Creation was 5810 instead of 5792 BC.
However, in our most recent documents we have adopted a date of 5680 BC for Creation, which reduces the chronology by 130 years. The reason is interesting. As the atomic clock data are compared with orbital data using the redshift correction curve, as is done in Dating the Geologic Column in our paper, Data and Creation, then we find that the best fit to all data sets occurs if 130 years are subtracted from the Alexandrian LXX chronology. It is important to note that this extra 130 years occurs in the Genesis 11 genealogy where an extra Cainan is inserted into the text with an extra 130 years. There has been a lot of discussion among textual critics as to whether or not that extra Cainan should be there. Without buying into the debate on this, we simply note that the best result is obtained from the data if that Cainan and his 130 years are omitted!
The most recent work is summarized in Table 1