What operating system are you using I used to have a unix scriped which used awk to extract the information from the file. I have found some notes on the script which may help. If you open an assembly file and read through it you will find 3 parameters @model_name @model_type and @bom_count these should point you at the information required. and with a littel bit of programing you can generate a single level BOM
I hope this helps
I will try and look out the full script, but have moved companys since.
Regards
Andy