I beg to differ. Having sequences out of order means that you lost some data.In his example 4 rows are missing, each one for a multi million order that disappear from the books.
You must stop transactions against the original database in cases of migrating the database to a new server.
Adar Yechiel Rechovot, Israel Hemant K Chitale wrote:
b. Generate a CREATE SEQUENCE script with values higher than the current highest and use such a script at the target