No, the “minimum” in the name refers to a minimum (proportion of time) over all windows. See link in GP and the thesis referenced there for a discussion of the dependency on the window size (which is a bit funny for all allocators).

That's just false; I can't think of a GC that can maintain more than 0% utilization in a time-window the length of a compare-and-swap operation (which could be 100s of cycles on some CPUs)