Index uses more pages after unload/load (?)

I have a table that occupied 9543 data pages and 1320 index pages. The table was unloaded using the "UNLOAD TO" statement. I had cause to drop and re-load the table, and I specified the initial extent as 10863 pages (converted to kbytes). The resulting table filled 11171 pages (9543 data, 1628 index). My guess is because of the FILLFACTOR setting. Previously, the index pages were closer to 100% full, and now they are at 90%. Is this correct? Should I be looking at something else? TIA. -- Paul Schaeflein