Compact does NOT defragment a database.
Compact consolidates freespace WITHIN a database, it has nothing to do with file fragmentation. In fact using a Compact -C is likely to result in a fragmented file.
A Domino NSF is just a file on disk. As Domino grows a database it asks the operating system for space - this additional piece of the NSF file can be anywhere on the disk - anywhere!
I hate reading articles that part way through say 'continued on page X' - they are a waste of time. Well imagine reading a book that said 'continued on page X' after each paragraph. That's what it is like. It would be slow, painful and time wasting.
Defragment your databases, reduce your I/Os and improve your throughput. Spend less time looking and more time doing.
Repeat after me, COMPACT DOES NOT DEFRAGMENT A DATABASE.
How healthy are your servers ? go to Defrag.NSF and check.