Not sure if I got shorted, but I received a partial refund. 4 days ago, I booked the cheapest option at the time, which was L-fare outbound + K-fare return. Now K opened up on the outbound, yielding a ~$100 difference.

Called Premier desk, and they transferred me over to web support. Web support validated the fare difference, and issued a voucher for ~$50 (difference less $50 processing fee). I suppose that's better than nothing.

In summary (for my case),
- As long as you purchase from United, you're eligible for the price adjustment. (I booked through the phone, due to site issues that day.)
- Cabin and flight has to be the same, but not fare class.
- $50 processing fee.
- Claim has to be within 30 days of purchase. I asked the agent for future reference.