Different compression for exact same image on mutlisite

Hi,

I have found a small issue with this great plugin. I have a WP multi site (multilanguage), so unfortunately I have to upload the same images twice. When uploaded, all images are below 1024×1024 px.

Here is the problem, at my main site the images are compressed better then at the second site.

Here are the numbers from the main site:
TOTAL % REDUCTIONS 29.82 %
TOTAL SIZE REDUCTIONS 40.62 MB
TOTAL RESIZE SAVINGS 35.17 MB
ATTACHMENTS SMUSHED 234/234

From the multisite:
TOTAL % REDUCTIONS 8.66 %
TOTAL SIZE REDUCTIONS 5.82 MB
ATTACHMENTS SMUSHED 231/231

I have here no resize saving. During bulk compression I forgot to make the maximum image size 1024×1024 and I can not improve my images now. Hitting recheck images button makes no difference as it says that all images are compressed fully.

I like the figures of my main site better and want to make the second site the same; the capabilities of this is possible as it is shown in the main site.

How should I proceed to make the images in the second site the same as the main site?

Thanks in advance!

https://wordpress.org/plugins/wp-smushit/