Originally Posted by
npretnar
The reason you would want to do this is that it seems the agents are pricing you out a new one-way fare, rather than the discounted round-trip fare which is often less or close to the same price on TATL itineraries.
They shouldn't be, it should be using the historical pricing on the back half of the original return as long as it's within ticket validity.
My guess is the second agent isn't familiar with the after-departure conditions and is mistaken. I'd suggest OP tries again, and has them confirm with the fares department if they suggest a fare difference - hopefully they're corrected and the difference it minimal.