I can confirm it.
The DHS blades I tried (PG5X, PG6X, Sun Yingsha, 301, 506X, Fang Bo B2X) had huge sweet spots, especially the Viscaria-alike (PG6X, 506X). The blades from YInhe (Pro 01, Pro 05, 970XX K, Y-series, T-series) had a much smaller sweet spot, almost twice as little.