Scarab type drop chance clarification

A quick question, does "increased chance to be x type" on the atlas tree means my chances are increased by x% compared to base one, or are they now higher by x%?

Say, I have 100% increased chance to drop sulphite scarabs. Does it mean I'll drop only sulphite scarabs (increased by x%), or will I see twice as many now (x% higher base chance)?

Can't find the answer anywhere.

You'll see twice as many now assuming it's the only source of increase.

100% of base, which is unknown. The word "increased" tells you that. 100% increased chance means there's an unknown base chance, a base to be increased. All scarabs have different base chances of dropping, I would assume.

Thanks, seems to be in line with my experiences. I'm asking because scarabs tied to my favourite activities are very cheap, so I don't want to brick my atlas map like that. But I can live with the double amount.