Natalie,
I am not researching the Sombrete area however in response to your questions perhaps I can help a little.
The title of the film you are reviewing tells me it is of baptismal records of the church of San Pantaleon. It is possible the film contains entries from other smaller out lying churches under San Pantaleon. I have found similar instances where the same person is recorded in two locations within the same parish. I can only surmise the smaller church records were systematically transcribed into the main parish records. This would centralize information making the periodic inspection of records conducted by the church simpler, meaning the Bishop did not have to visit every little church on his visitation trips.