Keeping the used space of the pool below 50% when using iSCSI(zvol) is not needed anymore?

[woyaojizhu8]

https://www.ixsystems.com/documentation/freenas/11.3-U2/sharing.html#extents : For performance reasons and to avoid excessive fragmentation, keep the used space of the pool below 80% when using iSCSI.
https://www.ixsystems.com/documentation/freenas/11.1/sharing.html#extents : For performance reasons and to avoid excessive fragmentation, keep the used space of the pool below 50% when using iSCSI.
Any details?