after some experiments:
- the fonts works OK in notepad - which means that probably the problem is in office 2013 and not in the OS itself.
- since the font is registered as restricted with respect to the "embedding" ability i thought that it may be due to this restriction, but nevertheless, removing the restriction ( i recommend on TTFPatch utility didn't change the behaviour.
- interestingly, i found that saving the document as PDF resulted in correct rendering of the font - which is pretty satisfactory to me.