Disadvantages can be seen like that the slip coach will have only 1 EOG and since the distance YET to be traveled would be less, the fuel in EOG should be sufficient.
If the Slip is delayed, it can hamper the TT but over all as said, for lesser distances travel, the delay can be minimal.
Food is anyways loaded into the PC and so,it should be ensured that slips traveling further should have the PC.