I'm not into all this new phone stuff and only use a Garmin Legend HCx with the Wyoming chip. Since I've had it it has always been accurate within 15' or less of any legal boundary marker that I could match it up with for accuracy. Since fences don't mean squat out there I would not be without it if I was hunting anywhere near private land. I would think as good as the company products are that what you're talking about should be as accurate or better than what I have experienced with my GPS. Even the 50 yards that you mentioned isn't bad, but I'd want something that's closer and that's why I've been very happy with my chip.