I think months is a slight exageration. The plays off finish this year on the 27th May so until these are finished, the league bodies cannot compile fully as they don't know 100% which teams are going to be in each division. EPL fixtures released 12th June this year, EFL 19th June although the clubs get them slightly earlier.. Sky Sports/BT Sports will have their first lot of TV fixtures out around early July and between these points, clubs will liaise with police etc. A good example is either Liverpool club being drawn at home this Saturday but due to policing, they'd move because of the Grand National.