Chucklehead - I think the VTOSS climb is more to do with angle of climb than rate of climb which, as you say, will be better at 60 kts (I think it says 56 kts in the RFM).
Certainly following an engine failure at or after TDP, the attitude change to capture VTOSS for the climb ensures you get a healthy vector away from the ground.
i think all your reasons for backing up are extremely valid - that's probably why the profile is designed that way.
Helitester - perhaps Nick Lappos has an answer to that apparent anomaly.