Maxxx, I believe Roygee is correct here.  The Inset Faces button/function has been used as the tool for insetting polygon groups of faces in Blender, since 2.6.  While the original Inset Polygon addon was introduced in 2.63, it was never intended to create the inset type you're expecting from the 3dsmax Inset workflow.  It's a bit confusing, but Inset Polygon is not the tool to use for face groups, but the hotkey still works correctly because it's been seamlessly assigned to Inset Faces since Blender 2.6.  Unlike in 3dsmax, in Blender, there are two completely unique inset tools, which are intended for different objectives.

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