If requested online during booking, I've found it totally hit or miss. This week, one should have cleared at booking. It didn't, I didn't notice. When I called in after checking in, agent just kept telling me "you'll probably get it". When I explained I was 9 on the upgrade list and that didn't seem right, she had no idea why that would be odd. Eventually convinced her to keep trying, she realized that there was space available immediately, put me on hold for 30 minutes, came back and it had cleared and the return RUC was applied correctly at check-in for wait list.