On the L airways in the western sector of NY oceanic, the airways between the US Northeast and the Carribean, the rule is even levels for northbound and Odd levels for southbound. because the magnetic heading of these airways is 004/184 Simbrief plans these the other way round. Perhaps this can be changed in the future.
Source: https://www.faa.gov/air_traffic/publications/atpubs/aip_html/part2_enr_section_7.13.html