what is a camp????They are marked by two markers.
Think about it - if it takes two weeks to mark Modern History with two markers it would then take five weeks with five markers (English which now takes 4 weeks to mark would take 10 weeks). You wouldn't get your results until February.
Having more markers won't reduce the discrepancy necessarily as most discrepant scripts I have come across in 20 years of marking are so because of one of two reasons - either it is one where there are two clear camps - one high and one low (hopefully both are high), or where one marker has simply misread something and gone high or low so a third marker can fix it.