Conclusion: towards the knives with only 1 hole worth this reversible blades with 2 holes just do not!
Idea is good - the reality is that the knife in the cutting-practice simply "gummy" - that is, if you installed such knives, then a few days / weeks can mow the Automower so, and you then this double-hole diameter turns for the 2nd hole is mande facto a fuzzy old knife! Sorry - that's a fact!
The blades are then completely black (through the grass juices) and no longer sharp!