I have written several threads on this topic and have never gotten any resolution, but I think I have figured it out.  We have several routing sequences that have been deleted from the master routing for the part but work orders had already been created for them and the deleted  routing sequence was not taken out of the work order.  When calculating estimated costs in the work order, this made all of the labor go to 0.  Making sure that the work order  doesn't have any sequences that aren't in the master routing  fixed the problem (the order the deletions are done in doesn't seem to matter) Yea!!

It was not that the sequence had zero labor,although it did, but that the sequence didn't exist in the master routing, since it had been deleted, but it still existed in the work order.  We had two deleted sequences in the routing I was looking at, and the first one was the first sequence, so my costs were coming up as zero, since it disregarded any sequences  after the one it couldn't find.  When I fixed that one, estimated costs showed for the sequences up to the second sequence it couldn't find.  When I fixed that one, they all showed up.

Well, I just tested it out and this is what I found: If I added a sequence to a work order amd not to the master routing everything worked fine ( it didn't matter whether it had 0 hours or not).  If I created a work order and then  took away a sequence from the master routing and left the sequence in the work order the recalculate estimated costs didn't work.