my case: Opt from 1/2005 to 12/2005;

worked for A company using Opt, A company applied H1 for me, H1 was effective in Oct 1, 2005;
9/2005 before H1 was effective, transfered H1 based on A company to B company; H1 transfer was approved by premium process in Sep 9; started to work in B company in 9/15/2005.