Altering column from INT to BIG INT and fill factor trick

I have inherited a script that rebuilds the fill factor sitting at 90 fill factor on the INT primary key. It rebuilds it at a fill factor of 50. Then the script drops the index, alters the column to a BIGINT and rebuilds the fill factor back to its original 90. Does that make sense to anyone? Are they doing this to grow space? Seems like as soon as they drop the clustered index, the space is a moot point. Thoughts on this?