I noticed this on this quote on the AFP548 website.

AFP548 - Tiger Server Overview:
Wrapping up

Apple has said that they are going to slow down the pace of major OS updates with 10.4. With all of the new features that Tiger brings this is a pretty good idea as the additions of GUIDs and ACLs alone will take some time to really get the hang of.

AMP is only cost-effective if Apple releases paid versions at least every 18 months, so unless we see increased value or reduced pricing, I don’t imagine that we will renew our contract.