I think as long as you have the repair as a type N part and no standard cost assigned that there is no need for the sequences. I know at one time I had the same problem by not following the sequence, but it had something to do with the way it was set up. I believe there was a post on this way back when.
Ragine

We use a part number REPAIR ORDER for our repairs.  The part number does not have a standard cost because the repairs can be quite different in materials and labor and therefore cost.  There IS a  problem with this if you finish a second work order with very different cost before invoicing and posting the first repair.  This is because the SO takes inventory at average cost not actual cost for the work order.  Also, the work order is not really connected to the sales order, it was just generated by it.  In other words, you could convert SO 2000 to a work order 2000-1, complete the work order  and sell it on SO 2010.  
Since the invoice reports in the SA module use average cost as the cost field, our solution is to produce a report using Access that can link the WO and price using the work order file that has a SO field (since it was converted) and the invoice file which also has a SO field.

This may be slightly OT, but I am the service tech for my company, so I primarily use DBA for entering customer repairs and parts.  Essentially, programs like DBA don't handle repairs very well.  I use sales orders to enter repairs, with a a part number for Labor.  This works fine for customer repairs where they are paying for it, but warranty repairs are a different matter.  Essentialy, the cost to the customer is zero, but you may want to get a report for what the repair costs you, i.e. your parts cost, inside labor, and shipping (if the customer isn't paying for it).
Also,  most good repair invoices would have a section for the data on the equipment being repaired, following by a section listing parts & labor.  In DBA, my workaround is to comment the equipment type and serial number after the Labor line.