Are Philips "LongLife Ecovision" and "X-treme Vision +130%" offered in an HB2 DOT marked version, or only H4 ECE marked? If there is no difference between the HB2 and H4 Philips bulbs in their respective lines, why are they (sometimes?) not dual-marked (H4 with ECE mark, and HB2 with DOT mark)... marketing?