2LIS_13_VDITM Some Delta Records are Missing

Hi,

We are having trouble on some missing documents for 2LIS_13_VDITM. We had a fill setup last July 8 for a certain company code at 8pm, and it finishes for about 7-8hrs based on the duration of 476.7 mins shown on the Log for setup data. The delta initialization w/o data transfer in BW was set at 8pm also. how come that there are some missing documents now for July 9-13,2015? these are 5 days data. can anyone explain the logic behind this?

Thanks,

anne