Provided that a) you are not making any changes to the outbound, b) that both your outbound and return are on the same ticket, and c) your new return qualifies for the same fare as your old one, then there is no disadvantage to making the change now as it will reprice using the same logic in both of the scenarios you describe but you may have access to better inventory today. If not, you should probably wait. If you wait, you may also get a fee-free change due to a schedule change or IRROPS.
Last edited by Sykes; Oct 10, 2013 at 10:54 am
Reason: Clarification