The question is really in the title. I replaced a standard outlet with an iDevices Smart Outlet (not GFCI, but same concept). The original outlet was in a 4"x 2 something handybox. When I swap it out for an outlet that takes up more physical volume on the inside of the box, do I need to recalculate the volume of the box to ensure there is actually enough room? The only reason I ask is that I had to really move wires around inside the box to get this much deeper device to actually fit.
do I need to recalculate the volume of the box to ensure there is actually enough room?
Short answer: No
As you found out some devices are larger than others. However, the National Electrical Code doesn't distinguish between them and every yoke mounted device counts as a double volume allowance. See Article 314.
Realistically, I would use a deep device box on every device when doing new work to allow for these kinds of devices.