On the topic of room size and upgrading, I have an upcoming three-night points stay at the end of August. We just decided yesterday that we will be bringing our 4 yo son with us, so will need a rollaway. It seems like it might be tight in the base level room, so I was offered to upgrade to a Luxury room for 15k JPY/night. However, as a Titanium, I feel like my odds of a free upgrade at check in are pretty decent. Is it worth it to pay for the Luxury room as insurance against not getting an upgrade? If I do pay for the Luxury room, would my odds of an upgrade probably decrease for any reason (other than that there are simply fewer room categories above it)?

thanks in advance for your thoughts!