The foam is in 1/8" layers. Blades cut slices. What else can you expect? One of the better targets for broadheads is the Yellow Jacket by Morrell.

The GlenDel buck, if using the layered insert will do the same thing as the Block.

The other option is what I do. I practice a lot. Probably shoot an average of at least 5000 shots a year.I tune my bow so that broadheads and target tips hit the same POI.The only time I practice with broadheads is to check the flight and impact point of each arrow with blades on. The I put them away and use "practice" tips (field points). That's what they're for. I see no advantage in shooting broadheads all the time.