[Plugin: CW Image Optimizer] bulk optimization information

What is the meaning of the lines below each filename during a bulk optimization? Does it mean that it does several optimization rounds for each image?

Processing dscn0036…
– Reduced by 4.9% (460 B)
– Reduced by 3.8% (685 B)
– Reduced by 4.0% (4.1 KB)
– Reduced by 18.4% (372 B)
– Reduced by 3.7% (834 B)
– Reduced by 3.7% (1.4 KB)
– Reduced by 11.9% (404 B)
– Reduced by 20.0% (372 B)
– Reduced by 4.7% (496 B)
– Reduced by 13.6% (377 B)
– Reduced by 8.4% (416 B)

Processing 3ni…
– Reduced by 2.1% (33 B)
– No savings
– No savings
– Reduced by 1.9% (59 B)
– No savings
– No savings
– No savings
– Reduced by 0.8% (16 B)
– No savings
– No savings

Using CW Image Optimizer 1.1.8

https://www.ads-software.com/extend/plugins/cw-image-optimizer/