1. I think you are actually giving up a year of your upper limit of income... For arguments sake, lets just agree that there is an average amount of time one spends getting towards the point where they roughly approximate the high point of their income. This would be the time needed to work as an associate, buy a practice, build up said practice, etc. We could say that the amount of time to do this would be the same whether one graduates at 26 or 27. If it were to take 10 years to do this, and you retire at 55, then one person makes their upper income from 36 to 55 while another only makes this income from 37 to 55. Note to those that will quibble with the average amount of time to reach the upper end of their income, insert any number you like, the logic still stands.
2. If you reject #1 completely, then remember that the first year income of $120k has a time value as well. $120k invested for 29 years would take a large chunk out of that $300k. Maybe beat it if well invested, and that's a chance I would take.
I think we have agreement though. If offered an acceptance, take it.