It's due to AAHA recommendations following steroid exposure. From what I understand, steroids can keep glucose artificially elevated for a while and then cause really bad hypos once it lifts. Raising insulin can make that risk of a bad hypo more severe. I can of course check in with the vet after one week if it seems that he's not getting more appropriate numbers though! Reductions will also be made if there's a hypo, of course.
This is the troubleshooting guide I am referencing by the way:
https://www.aaha.org/aaha-guidelines/diabetes-management/troubleshooting/
And it would only be a total of two weeks, including the days since the one marked "day 1"