There are several things that can affect the temp reading. Stove setting #5 is approximately 75* (give or take - it isn't necessarily exact, but a set point).
The air temp probe is near your stove, so it is measuring warmer air than what is in the general house. Raise your stove temp until your house (where you are recording the 71* at) is where you want it. Or, you cold find a somewhat cooler location for the temp probe to rest at (maybe closer to the rear of the stove). Moving the probe, although it would seem easier, can be frustrating becuase of teeny, tiny air currents that can have an outsized effect on what it reads. Also, it is easy to mistakenly move the probe (pets, kids, cleaning etc).
Your feed rate may not allow for that, so you may need to raise it to 4.0 or higher (I would leave it at 3.5 until you have established that it is not the above issue).
Pellets, in this instance may make a difference. If you are burning middle of the road pellets, you may need to go to hotter pellets (either a SW, or a premium HW like Cubix).
It also depends on where you are measuring your actual air temp at. If it is in another room, in a corner behind the stove, or at the far end of the house, it is natural that it would be cooler there than closer to your stove. I set up a wired thermostat for my stoves. For the main floor stove, it is because I wanted my office at ~69* while I am working there all day. In the basement, there were other considerations (which I won't get into).