GH5 vs GH6 - Performance of "Solid Difference"

I noticed that a “Solid Difference”- Operation between One and Many objects takes about 40% longer in GH6 than in GH5.
The Rhino unit tolerance in both files is set to 0.001 as this is the only setting that influences the performance of Boolean Operations as far as I know.
Is there a known explanation to this? (17.6 KB) (12.3 KB)
SD_GH_RH5.3dm (1.3 MB)
SD_GH_RH6.3dm (1.2 MB)