When expanding an ArcGIS Server site from one to three machines, the number of ArcSOC processes (service instances) will increase proportionally. For dedicated instances, each service's minimum and maximum instances are configured per machine, so tripling the number of machines will triple the number of dedicated ArcSOCs. For shared instances, the shared instance pool runs on each machine, and the number of shared instances is configured per machine. Therefore, the total number of ArcSOCs (both dedicated and shared) will be approximately three times greater after the expansion