Yup....it is a one tine good deal for your first Captain upgrade. Remember though, you do carry any prior training committment with you and that gets added to your 2 year Captain upgrade. There are at least two guys in NYC who had nearly 4 years of seat locks - one was awarded NYC330 F/O and then bid NYC717 Captain a month or two later and another was awarded NYC717 Captain and then bid NYC A330 F/O the next AE (not seat locked because the NYC330 was still considered a new category at the time).

So.....really 4 ways to break a seat lock - Mandatory Displacement (no training committment); Voluntary Displacement (training committment); New category (training committment) and First-time Captain upgrade (training committment).