Rick, I have a 2002 Elantra. BOTH of my son's (low beam) headlights burned
out late last week, and I had to replace them both (have been using the
Sylvania SilverStar, which has made a huge difference in the brightness of
the headlights, but which, unfortunately, have a relatively short bulb
life).
That 'tab' you refer to is to go UP, not down. If you hold the bulb by its
electrical connectors (the only way you are supposed to), and keep spinning
the bulb around, eventually, you will find the proper detent, and you will
see (especially from the outside) that it is in correctly.
When I replaced both headlights, the notch was straight up, and the
connectors on the back of the headlight were one straight on top of the
other. They look right, they are aimed right, and they work great. Sadly,
the only way you know it to look at the bulb from the outside, through the
lens. Also, you will have a bit of a time getting the retaining spring back
on if it is not on right. And bluntly (thoough this is subjective), it just
won't feel right.
Having a Kia Sedona minivan that uses the same headlights, and the same
logic, this job is getting simple for me.
Hope this helps.
Tom Wenndt