The sharpened trailing edge was introduced for two reasons, as I recall this from conversations with Markus in 2002:
1) make for better withdrawl from targets
2) add cutting surface for the instance the arrow will not pass through
I did hundreds of test shots in 2003 - just after Markus had hit the market. Compared with any other 2-bld head I shot SF's were by far the easiest to draw from bales, even though others had a steeper blade angle on the trailing side. This really works and is big benefit for your training options. You don't need foam targets and would be able to invest the saved money in SF's instead
I came to test point no.2 also ...
BTW: I will not comment on the 100gr SF