I am not a "Trane" guy but I am a fairly seasoned hvac guy. The stat is single stage heat, and your furnace is probably a 2 stage heat furnace. Which means it can run at a lower btu. rating and if it needs to, kick into a higher btu. furnace (give you more heat).
You could have a 2 stage thermostat do this for you, but I prefere the furnaces "timer" to do it. Which means that if the furnace is on for ten minutes and doesn't satisfy the stat the it automatically goes to "high" fire. Its possible that you don't have enough strands at the thermostat from the wire to do a 2 stage furnace, so yes, the thermostat is OK and capable. You would need to listen to the furnace for 8-12 minutes to hear it shift up to see if your contractor flipped the dip switch for this option
BTW, sound like you chose some nice equipment.
As iron sharpens iron so one man sharpens another Proverbs 27:17 NIV84