For people who don't already know this, when you find an entry of interest in the IGI you also need to look at the bottom of the screen to see whether or not it is an extracted entry (from the parish register) - other entries cannot be trusted.
Also at the bottom of the screen is the Source for that particular entry, which will be a parish register film if the entry has been extracted. If you click on the film number you can see what else is contained in that film.
The LDS did several filmings of most parish register official copies, which is why looking at the source given with the particular IGI entry is crucial. Some films omitted some years, or started and ended at different dates.