A cross appeal occurs when both sides appeal the same order. As the Appellate Division can only grant relief to the side which takes the appeal, a cross appeal is fundamentally different than a typical appeal as neither side is requesting to maintain the status quo of the lower court's disposition of the case.
Normally, the side taking the appeal will try to focus the arguments as questions of law, while the side seeking to defend the appeal will try to focus the arguments as questions of discretion. The reason being is the Appellate Division is more likely to revisit a question of law, while questions of discretion are greatly deferred to the lower court.
In cross appeals, neither side will be arguing for to maintain the status quo, which removes a key element in opposing the other side's appeal.
The procedural rules for cross appeals are also significantly different than when only one side appeals.