Plus the fact that DUS has to be one of the fastest airports to get out of and back into. It really is quite small, and once you knock out Lufthansa at the A Gates there's not much left. Not sure the agent would be right about OLCI either, so long as it shows up ok on the BA side. As an example, I flew recently to MXP on an AA codeshare, BA metal, 2 booking refs, one for AA (visible on aa.com) and another for BA (visible in BAEC). OLCI worked fine on BA.