ok, here's the thing

i'm scanning merged sets + allow not separated bios roms

here's the log for 3 arcade sets (using logiqx's dats)

FB Alpha

no problems with currently set options

----------
Missing Sets:             1 of 490
Wrong Spelled Sets:       0
Wrong Named Sets:         0

Missing Roms:             3 (3 are 'nodumps') of 7475
Wrong Named Roms:         0
Wrong Spelled Roms:       0
Wrong Sized Roms:         0
Wrong CRC32s:             0
Wrong MD5s:               
Wrong SHA1s:              

Missing Samples:          
Wrong Spelled Samples:    

Missing DiskImages:       
Wrong Spelled DiskImages: 
Wrong Named DiskImages:   
Wrong CHD_MD5/SHA1s:      

Unneeded Files/Folders:   0

Number Of Sets:           490
Number Of Parents:        101
Number Of Clones:         255
Number Of Others:         134
Number Of Roms:           7475
Number Of Samples:        0
Number Of 'nodump' ROMs:  3
Number Of 'baddump' ROMs: 0

no problems with currently set options

----------
Missing Sets:             2 of 411
Wrong Spelled Sets:       0
Wrong Named Sets:         0

Missing Roms:             0 of 6293
Wrong Named Roms:         0
Wrong Spelled Roms:       0
Wrong Sized Roms:         0
Wrong CRC32s:             0
Wrong MD5s:               
Wrong SHA1s:              

Missing Samples:          
Wrong Spelled Samples:    

Missing DiskImages:       
Wrong Spelled DiskImages: 
Wrong Named DiskImages:   
Wrong CHD_MD5/SHA1s:      

Unneeded Files/Folders:   0

Number Of Sets:           411
Number Of Parents:        88
Number Of Clones:         200
Number Of Others:         123
Number Of Roms:           6293
Number Of Samples:        0
Number Of 'nodump' ROMs:  0
Number Of 'baddump' ROMs: 0

no problems with currently set options

----------
Missing Sets:             15 of 4640
Wrong Spelled Sets:       0
Wrong Named Sets:         0

Missing Roms:             142 (142 are 'nodumps') of 67305
Wrong Named Roms:         0
Wrong Spelled Roms:       0
Wrong Sized Roms:         0
Wrong CRC32s:             0
Wrong MD5s:               
Wrong SHA1s:              

Missing Samples:          
Wrong Spelled Samples:    

Missing DiskImages:       
Wrong Spelled DiskImages: 
Wrong Named DiskImages:   
Wrong CHD_MD5/SHA1s:      

Unneeded Files/Folders:   0

Number Of Sets:           4640
Number Of Parents:        1027
Number Of Clones:         2018
Number Of Others:         1595
Number Of Roms:           67305
Number Of Samples:        2010
Number Of 'nodump' ROMs:  142
Number Of 'baddump' ROMs: 0
notice the missing sets? what's up with that?
i don't notice any pattern among the 3 logs, i can't think of a reason why this happens

so, what do you think Roman?