this wording change is even more ambiguous now
Average Party Level
In order to determine which subtier a mixed-level group
of PCs should play in, you must determine the group’s
average party level (APL). You should always round
this number down. In addition, because encounters
are designed with four players in mind, if there are
six or more players at the table, add +1 to the APL. For
example, if a table consists of six players, two of whom
have 4th-level characters and four of whom have 5th-level
characters, the group’s APL is 6th (divide 28 total levels by
six players, round up, and add +1 to the final result).