They went overkill on the imp's.
John has a platoon:
1 command squad
1-3 squads of standard guys
a few squads of conscript (a normal conscript squad being 50 men)
1-3 heavy weapon squadrons
and this rule that means that although he can't shoot with them for his turn, they benefit from a 2+ cover save.
his lemun russes are now in squadrons that count as 1 heavy choice on a data sheet.
he can have 9 lemun russes on the field (STANDARD).