World Partition: Foliage Actors': Not streaming out cleanly

[TheRealBiomes (RealBiomes)]

In World Partition, Foliage gets split into various blocks, called foliage instanced actor.

Sometimes, blocks of foliage that should be streamed out (ie beyond the grid distance) do show up.

But only some and only sporadically. It looks like patchwork. Only one Grid exists so it can’t be a problem with varying grid settings.

[TheRealBiomes (RealBiomes)]

A World Partition related feature that will pop up for most people making a massive natural world and using the WP tech.

World Partition: Specify Grid per Foliage Type

It would be great to have some Foliage Types be streamed in most of the time: ie trees that can be seen from far away. And then any dense, small stuff like bushes and small rocks would be streamed in only when the player is fairly close. For that, it would be great to be able to specify a World Partition Grid per Foliage Type Actor. In order to differentiate between the large trees and the small shrubbery/bushes. Is this already possible somehow?