Planning Worsheet - strange result

My BOM structure is as following. Finished goods 1100100001 … Part 1 1001200001 ---- Raw material 0300109000 … Part 2 1001200002 ---- Raw material 0300209000 … … Part 300 1200300001 — Raw material 0400109000 … All items are MTO. Reorder Policy is Order. All items inventory is 0. I create a Sales Order for finished goods 1100100001. Then I run planning worksheet with MPS&MRP. The system only show me the finished goods and those items after 1200300001. Then I refresh the line of finished goods, the sytem shows all items of its BOM include 1001200001. The result is so strange. I guess maybe the reason is the item No… I use 10 digitals as item number. And the finished goods has more than 400 parts. Every part has its BOM which has one material only. So I change the finished goods’ number to 9 digitals, that means it’s at the beginning of the item list. When I run planning worksheet. I got all items shown out. Anybody has similar case? Is it a Navision bug?

I solved this problem myself by runing Calculate Low Level Code. So please remember the Low-level code is very important when runing MRP! [:)]