DL awards to/from US/Canada largely correlate with revenue fares with multiple award levels on any given route -- cheapest award levels require roundtrip booking and advance purchase requirements on many routes (just like cheapest revenue fares). The requirements are disclosed in award fare rules just like revenue fare rules. Yes, they will be much higher if only looking at one-way awards and comparing to programs which still use fixed levels and roundtrips are same as two one-ways.