Send me a link to the A2-73 expiration of the Greek patent. Also show me where in the PR the 2015 issued patent says it is for 2-73 and not "related to 2-73". Then look that patent up and see if it is for 2-73.
Here is an article states the original patent was issued in 1997. It does not mention a month...also I don't know how long Greek patents are good for or if it transfers to the US year for year.