Glad you were able to put a Y-Up to good use. Do be aware, though, that often it can actually be cheaper to book an R fare than to book full Y (assuming R fares are available on the route for the date and time you need). By booking an R fare (an actual First fare class), you also protect yourself in the event of missed connections or equipment swaps. In such cases, you would then be treated as a displaced F passenger. As a Y-Up passenger, you might end up flying in the back of the bus under such circumstances.

Whether Y is cheaper than available F fare classes depends on the route. However, I was recently able to book IAH-SJU with an R fare at approx. $750 all-in. The Y fare on the route was selling for over $1,000