Yes, thats correct. All of the BMW plans for all levels (powertrain+, gold, platinum) for all vehicles under 4yr / 50k are from the "in service" date. For me, that's May 2010. For anyone over the 4yr/50k original warranty, only the powertrain+ level is available and the "clock" for those plans is reset to the date you extended the warranty, but they are only offered as 1yr/12k, 2yr/24k or 3yr/36k. Hope that helps.
2010 335i Jet Black-2006 330xi Sapphire Black-2005 325i Midnight Blue-2006 325i Sapphire Black