After a long discussion period, the decision has been made. All stainless steel MR blades must be replaced within 5 years. Estimated cost of replacement from $30k to > $100k per helicopter, depending on the affected model.
We are superseding Airworthiness Directive (AD) 2011-12-10 for Robinson Helicopter Company (Robinson) Model R22, R22 Alpha, R22 Beta, R22 Mariner, R44, and R44 II helicopters with certain main rotor blades (blade) installed. AD 2011-12-10 required inspecting each blade at the skin-to-spar line for debonding, corrosion, a separation, a gap, or a dent and replacing any damaged blade with an airworthy blade. [...]
This new AD also requires a terminating action for those inspection requirements [...] and to correct the unsafe condition by replacing the main rotor blades with new blades that do not require the AD inspection.
http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgAD.nsf/0/1c99426cc73ec86886257da5004f4e10/$FILE/2014-23-16.pdf