For3 enables the factory remote starter settings in the BCM. The whole system acts as the OEM Ford remote starter. The default setting in the BCM for heat and A/C is set to Auto which is about 22 degrees. It will not use your "Last settings". You can actually have those settings enabled at the dealer so that you can then control everything from the cars user menu as if it were the OEM remote starter. To get an idea what im talking about, https://youtu.be/G7j5R_w6OjI
The other option is to go with the EVO-FORT2 install if it's key start F150. Install is completely diferent and does not rely on how the bcm is set up. It's a standard remote starter install where it's the remote starter actually starting the car. Heating would then use whatever your controls were left at except for the rear defrost (defrost resets itself by simply turning the key off).