16 SEER Heat Pump New Install Question

I just had my central AC unit replaced in my 1500 sq ft home with a 16 SEER 3-ton American Standard heat pump system with a new 3-ton air handler and all new ducting. The system cools very well. It can reach 72ºF with outside temps of 95º+. Problem is the indoor air handler is very loud and we were in the impression that the system was an energy efficient, 2-stage unit. It seems to never operate at the lower, energy efficient stage that should maintain the comfortable temperature throughout the day. It seems to just cycle on at full blast and off. We also have the Ecobee Smart Thermostat Premium is set up for 2-stage cooling/heating.

Can someone please verify if my equipment can be set up for 2-stage cooling/heating? My model numbers are below:

[American Standard 3 ton heat pump 5HPL5036A1000A](https://www.tranesupply.com/product/5hpl5036a1000a/01t4w00000NkEa7AAF)

[American Standard 3 ton air handler P0V0A000M30SDA](https://www.tranesupply.com/product/p0v0a000m30sda/01t4w00000P7q0fAAB)

I'm just wondering if the HVAC company that installed the unit just doesn't have the skillset to set this up correctly.