Quartus 9.1 doesn't fit SCFIFO into M9K blocks, it prefers LEs. Why?!

Hi All, I've used the project Nios II UDP Offload Example (http://www.alterawiki.com/wiki/nios_ii_udp_offload_example) on a Cyclone III dev kit, using Quartus 9.1. It seems to work well. ...