@30knees - if you upload the img folder @ kraken.io it will compress it even further but I would not hassle to do so for 4-5% saved size, especially with the free plan where you can't upload folders.
Try resmush.it if you are into this type of stuff. I don't belive that 10kb less data on the product page will rank you first in your niche, many more factors are more important both on desktop and mobile than this.
Of course it's nice to see those numbers go higher/lower but most of the time they don't mean anything...