I'm using the CustomerSyncService in order to find what changes have happened in the last 5 days and when the last change was. The former works find however the last change timestamp seem to show the last time the account was viewed in the adwords UI.
I ran a test on an account that hadnt been changed or had any activity in a over a year, but when I ran the CustomerSyncService I got a last change timestamp of about 10 minutes ago, when I viewed the account in the UI.