FlyerTalk Evangelist, Ambassador, British Airways Executive Club
Join Date: Jun 2008
Location: Somewhere between 0 and 13,000 metres high
Programs: AF/KL Life Plat, BA GGL+GfL, ALL Plat, Hilton Diam, Marriott Gold, blablablah, etc
Posts: 30,520
I don't think that your understanding is correct. Having a HBO fare, as a silver member (or gold or nothing for that matter) your luggage entitlement is strictly 0 bag. When you "add luggage" you are simply paying for one piece of excess luggage in addition to that 0 allowance and that single piece is what you become entitled to.