Let's forget about the Home/Road half of this for a moment. If all we cared about was estimating his platoon skill ability, The Book says we need to add 1,000 PAs of average split performance (that is, Benintendi's overall line with a league average platoon split applied) against left handed pitchers to his actual performance. His existing 194 PAs are very nearly meaningless by comparison, forming roughly 16% of the regressed sample.At what point do those numbers become meaningful? If 92 PA isn't enough -- and you may well be right that it isn't -- what would be?
Now if we want to estimate his "at home vs L" talent, we are going to need to regress even more heavily, because we don't have any strong priors that the ability to hit same handed pitching in certain ballparks is a separate skill than simply being able to hit same handed pitching.
Put another way, you will be able to find some layered split like this that makes pretty much any player of Benintendi's experience level look similarly awful if you try.
In short, Benintendi shouldn't be platooned (certainly not with Mitch Moreland) unless his overall batting line continues to suffer for an extended stretch, or he goes annother 4+ years with similarly extreme L/R splits.
I know "we don't have anywhere near enough information" is boring, but in this case and in nearly every other discussion on platoon splits in this forum, it's easily the best answer we have.