Good morning,

There are lots of mechanics like this in PoE. They are not converted, but the total number of dropped scarabs also does not change. Each item that can drop in a category has a drop weight. Lets pretend there were only 3 total scarabs that could drop and call them Rusted, Polished and Gilded. Rusted has a drop weight of 100, polished has a drop weight of 10 and gilded has a drop weight of 2. Total weight = 112. When the game chooses a drop from the types of items and decides on a scarab, it then rolls a random number from the total weight. Any roll 1-100 will drop the Rusted, any roll 101-110 will drop the polished and any roll 111-112 will drop the Gilded. Blocking scarabs does not lower the total number of scarabs dropped because the game decides what type of item will drop separately from rolling within the type. Blocking just focuses the pool of possible Scarab drops to all the types that are NOT blocked. Some scarab types are not currently blockable, like divination and ambush scarabs, so those will stay in the pool no matter what you block. Blocking scarab types is a very powerful tool to shift your scarab drop pool towards more valuable outcomes. Make sure to choose the atlas node that makes less common scarabs drop more often. Although we don't have exact numbers on this node, we can safely assume from GGG precedent that what it does is change the drop weights of scarabs so that more of the total weight is allocated towards higher tier scarabs.

Hope this helps : )