I think true home field advantage is game specific. I too am old enough to remember the standard "just add 3 points to the home team" approach and know this has slipped substantially. The last two Raiders games I've attended in Las Vegas had the Raiders with no more than an even split of the fans, at best. I, however, don't think that's what has really effected the value of homefield advantage in the NFL, to me it's the ease of travel. Visitors just don't have to deal with the things they had to deal with even just a decade ago and definitely not what they had to deal with 30 years ago. I think from push rates and ATS numbers you can see that homefield has slipped but I still wouldn't be eager to bet Miami -6 in Green Bay in December or Minnesota -4 in Arizona in August without considering the home filed setup in both those vastly different scenarios. I know some smart players that use 1.8 as standard homefield now but, then again, they wouldn't be true advantage players if they actually just flat-rated homefield now would they.
I can see from the few bets you've listed and the nature of this query that you feel it's probably zero. I'm not sure that's the answer I would give but could respect the argument of someone who believed it.