James,
Loading that many cells in bulk into an NIS it is not recommended practice due to memory consumption.
Each cell imported into the NIS has an import version created as well, and these must be reconciled and posted one at a time to Default.
Recommended practice would be to import the cells in batch, but only perhaps 5-10 cells at a time at the most to avoid issues with maxed out memory in both the import phase and the posting phase.
Also it would be so much easier to keep up with the list of import versions if there were only a few at a time to post then 880 of them to deal with at once.
