Lamnia ‑ SKU Generator

It seems that this app can't see all my active products.
I've selected all the products it showed, 50 at a time, (since there is a limit on how many products you can do at a time) but still half of my items are without SKU numbers after I went through the entire list they provided me.
A "only show products without sku" option would also work great, or even showing collections.
Hope you can fix this issue, because I like your app