Based on the info in the promotional email, BNA-LGA was showing $129 o/w, for $258 r/t. Checked the restriction link -- advance purchase, travel OK Mon-Sat. the usual. But when I went to book the best I could find for several date combinations that conformed to the restrictions was $358 r/t. Web services found the problem -- No Sat. night stay required as per the email, but the fare basis -- which you can't see --was requiring it, a conflict likely for many fares in the promo. Web services honored the fare -- I had to book online and web services CSR changed the fare info in the record. Advise anyone else having trouble getting the advertised fares on this promo to call web services.