SC4020 over provision

I currently have a Compellent SC4020 that I use in my VMware environment. I have been using the SAN for a little over a year now and I present 4 volumes to VMWare with 2 being 4 TB and the other 2 are 5 TB luns. I use thick provisioning on the VMware side per Compellent recommendations since that side is thin and does not store zeroed out data which is what I do observe. The compellent side does de-dupe and compression per volume if enabled and I am getting an average of 2:1 dedupe on the system. This allows me to have slightly more storage available on the compellent side including RAID overhead which is a selling point of the device. However, support is concerned when they see the array over-provisioned which makes no sense if the free space is available and you are watching this our why else use thin. My array currently has about 48 percent free space but I have to over-provision because of the thick provisioning on the VMware side. Do other compellent users do this and at what point do you start looking at adding disks? Another thing to note is that the free space has stayed about the same since spinning the SAN up so currently I don't have massive data adds that don't get taken care of by dedupe and compression. My system is dual redundant with Raid 10 dm and Raid 6-10. Snapshots are taken daily and most Raid 10 gets pushed down to Raid 6 daily.