Upcharges for booking one way?
 

I am looking to book a few r/t award flights on LEVEL via the Iberia site (NYC-BCN), but I can't see the complete taxes and fees on the award tix until I move all the avios into my account (need to transfer chase/amex, etc). If I'm still waiting to confirm my return leg of the flight, is there a downside to just booking the outbound flight first? Is there potentially an upcharge for booking individual one-ways and is the best thing to book the full round trip once I confirm the inbound leg? Unfortunately I can't compare individual leg bookings vs. r/t because I don't have enough avios yet. Thank you!

It costs exactly the same to book 2 one-ways as 1 return.

The only difference is that you would be paying 2 sets of cancellation fees if your plans change. (offset by the advantage of being able to change one of your flights more easily)

Thanks so much for the fast response and the reminder about the separate change/cancellation fees. Really appreciate it!