"Hello.
Processing in Normal and VIP differs only in priority (VIP is processed before Normal).
About indexing issues.
This is strange, because now in general through the urls of all the clients of the service
the indexation rate is about 90%.
This can be google's filter on the quality of content. Or sometimes google's bot has some delay in indexing (1-24 hours, but very rarely).
Hope this information will help you to understand more about the indexing process:
I use some technical magic with Google Search Console for indexing. There is nothing "blackhat" in that technique, a lot of people (including me) using to index their white-hat pages.
This method is very difficult technically (and that is why is not cheap), but it has the highest indexing rate among the available on the market (you can check this very simply - just make simple split-test).
In fact, after that Google's bot visits your page immediately and if everything is good your page will be indexed in a matter of minutes.
In general through the urls of all the clients of the service the indexation rate is about 90%.
But if your pages are not indexed...
The problem can be with the quality of the pages (content quality + domain quality).
In fact, you should compare my service with some others to see which is more efficient. For example, if you have 100 links - shuffle them, split into 2 equal parts and try to index one of them with my service and other with any other service. And you'll see exactly which method is better on your links. And you'll see exactly
https://www.google.com/webmasters/tools/submit-url ). Or will be indexed, but de-indexed in a very short period (for example if they have low quality).
I create my own sites. It's easy to check different indexation tools with them because the domains are new so there are no filters on them. All links that I add are indexed in some minutes. And using server logs I see that Google's bot visits every page immediately after the service finished to work with that URL. And everything other depends only on google's conditions: "Note: The page will be considered for indexing only if it meets our quality guidelines and avoids the use of noindex directives."
To get the page indexed you need Bot + "quality guidelines". My service guarantee bot. If you guarantee "quality guidelines" your pages will be indexed.