That paragraph (+1 policy) applies only outside of US/Canada. (Otherwise, US/Canada would only be one bag, since standard allowance is 0.) Given that we have to stretch to read the text in that paragraph as clarifying the chart in full, then I don't think it's unreasonable to read "Medallion member" in the end for travel companions as shorthand for the full group of individuals having comparable status listed at the beginning. Probably best to verify with DL, but the response will likely be confusing. Baggage allowances when you've flying TATL but have been upgraded in advance for the domestic sectors are particularly problematic, as OLCI offers three bags, but phone agents insist that it will be a 50lb/23kg weight limit. I can't find anywhere in the chart that allocates three bags for TATL Y at 50lb/23kg, but that's what they tell me it would be.