We are a small medical device company selling products in the US and internationally including the EU. We are updating our listing of standards and wondering if we need to purchase both the EN version and standard version (i.e. EN ISO 15223-1 and/or ISO 15223-1). Also, on the EN version, is it feasible to shop around for best price? We currently have BS EN, DS/EN and just the ISO version. Thanks in advance for your comments and input!