u can check itn for the real situation before going to the airport.

i just looked at, e.g. 9/8, 9/9. there are 2 Y/B seats and plnety of J+ available.

when they expect the seats are tight, they tend to release the lower fare classes slowly, to protect teh revenue. and this is quite normal in tourist season, that is when the MPO Gold/Diamond guaranteed seat becomes really valuable --- in fact perhaps the "only" tangible benefit