Ramifications of serial control "sales order issue" for install base and various service modules

We are curious what the ramifications of setting our finished good products serial control to "Sales order issue" vs "at receipt" on the various service modules such as installed base, depot repair, teleservice.

We understand how the serialization works within inventory and that the product will only get a serial number once it ships.

Our question is what do we lose in installed base or depot repair when we have this setting.

When we do an RMA and the product comes back in house.  We notice it has 2 install base records for the item, one at the customer site that is serialized showing returned for repair, and another internal generic install base record for the stock sitting in inventory now.