Follow up re missing tier field in IM_ItemCost - have been working with Sage re this. We purged 0 qty lots a week or so ago and have had no new missing tier issues since. Client had about 3500 records, which certainly doesn't seem excessive to me, but since purge (down to 600-ish), have not had error. Of course, it's only been two weeks, but they had been having it pretty steadily once a week.
Now to tackle the incorrect Committed field.