Looks like your pretty far from me.I have WiFi $40, it’s new just no original box
What temperatures do you have set on the Helio controller, if you don't mind? I am wondering if you are asking it to heat to 76 and it is doing so and representing on your graph above. I have had some heat controllers do a good job of keeping a tight temp range but multiple degrees off of what I asked it to heat to. Kinda annoying but I just make a mental note and adjust.Below is the graph over 1 day