If you have new H1 I-94 starting Oct 1, 2005. Your non-immigrant status are fine (F1 before 10-1 and H1 after 10-1) so the key is that new H1 I-94 (part of the I-797 paper), do you have it?
If you do, no need to change back to F any more.
If you do, no need to change back to F any more.