I was reading through this thread - and I have a question, regarding the prices on CO and UA.

The flight is the same but there is about 150 dollars in difference.

This is a UA metal on 10/15 BOS-SAN 5:33pm depature through DEN.

The UA price for the flight is $600+
The CO price for the flight is $480

Wondering why the price for the same flight is that different in price?

One more the question I have is - if I book the CO flight on UA metal - how does UDU work?