Try changing your context constructor to this:
public ReportingContext()
{
this.Configuration.AutoDetectChangesEnabled = false;
}
EDIT:
This will after all not help you, as stated on Arthur’s blog, it is usable only in particular scenarios:
http://blog.oneunicorn.com/2012/03/12/secrets-of-detectchanges-part-3-switching-off-automatic-detectchanges/