ISINSCOPE ancestor leakage – add ISCURRENTHIERARCHYLEVEL() or ISINSCOPEEXACT()

[WithwindOK]

Today ISINSCOPE() returns TRUE not only for the column that actually defines the current row header, but also for every ancestor column above it in the same visual hierarchy. This makes it impossible to write a single, generic measure that can detect “exactly which level I am on” when users freely drag-and-drop fields in a matrix or chart. As a result, we are forced to hard-code every possible field order or rely on work-arounds such as calculation groups with manual slicers—both of which break the self-service promise of Power BI.
We need either:
1. A new function ISCURRENTHIERARCHYLEVEL() that returns the zero-based index of the current level, or
2. An ISINSCOPEEXACT() function that returns TRUE only if the column is the lowest-level scope for the current cell.
This would allow one measure to dynamically calculate “% of parent” regardless of how users arrange their hierarchies, without requiring visual calculations or visual-level functions. Please prioritize this model-layer capability for DAX.