Why such a large IP address range for analytics api?

[Simon.Parish]

I'm trying to get an allowed listing together for analytics.api.appdynamics.com.  We cannot use the DNS name and every document I have read says to look in the AWS ip address listing for the region that the DNS name is in.  This is US-west-2 and when I look for just the 52. & 54. Ip address ranges, this turns out to be 120+ and some of these listed are /14s.  Surely there must be some documentation that ties this down tighter as it seems to span high numbers of IP addresses, many I would think aren't used by AppD