Arc help

[kj911]

This different results, with variable one -d??? (or without) switches:

C:\Temp>arc.exe a -r -ds -ed -s -mlzma:ultra:64mb:mfbt4:fb273:mc1024:lc8 dds001.arc ROUTES
FreeArc 0.67 (March 15 2014) creating archive: dds001.arc
Compressed 15 files, 29,930,240 => 6,631,977 bytes. Ratio 22.16%
Compression time: cpu 31.06 sec/real 31.34 sec = 99%. Speed 0.95 mB/s
All OK

C:\Temp>arc.exe a -r -ed -s -mlzma:ultra:64mb:mfbt4:fb273:mc1024:lc8 dds002.arc ROUTES
FreeArc 0.67 (March 15 2014) creating archive: dds002.arc
Compressed 15 files, 29,930,240 => 6,646,220 bytes. Ratio 22.21%
Compression time: cpu 29.16 sec/real 29.39 sec = 99%. Speed 1.02 mB/s
All OK

C:\Temp>arc.exe a -r -dsns -ed -s -mlzma:ultra:64mb:mfbt4:fb273:mc1024:lc8 dds003.arc ROUTES
FreeArc 0.67 (March 15 2014) creating archive: dds003.arc
Compressed 15 files, 29,930,240 => 6,644,465 bytes. Ratio 22.20%
Compression time: cpu 29.05 sec/real 29.34 sec = 99%. Speed 1.02 mB/s
All OK

C:\Temp>arc.exe a -r -dses -ed -s -mlzma:ultra:64mb:mfbt4:fb273:mc1024:lc8 dds004.arc ROUTES
FreeArc 0.67 (March 15 2014) creating archive: dds004.arc
Compressed 15 files, 29,930,240 => 6,631,761 bytes. Ratio 22.16%
Compression time: cpu 30.98 sec/real 31.33 sec = 99%. Speed 0.96 mB/s
All OK

Does anyone understand this ??

The best and recommended (file sortings, solid archive) switches from compression?? -ds or -dses or -dsns or without -dxxx??

More examples contains -ep1 switches. My tests, not recommended. This minimal compression ratio differences, available in any external compressors (ex: LOLZ) and multigigabytes ranges? Tested from DLZ and get few kB's gains in few MB's compressed archive. (5466kB vs. 5432kB) without changing the DLZ compressors methods and switches. (Used: slp:d64m:lp0:fb337:cu3:cm43)