I have a late 2013 iMac running Yosemite and OS X server. I use this to cache OS X and IOS8 updates to my MacBook, iPad and iPhone as my internet connection is via satellite and is limited to 30Gb/month. Sometimes cacheing works ok on both OS X and IOS8 and other times it doesn't. There seems to be nothing consistent about it. As an example, last night I downloaded two IOS app updates. One appears to have cached ok and, after downloading to my iPad, installed on the phone in a matter of seconds. A second app doesn't appear to have cached and had to download from the app store again. Any ideas, please?