How important is that .1 quart?
2014 Crosstrek....hasn't burned a drop in 23k....found a 5 quart jug of QS Ultra Durability 0w20 for 17 bucks....of course it is in a 5 quart jug
So will my engine miss that .1?
You can safely round down to 5 quarts. In cars that call for odd amounts like that, I tend to round a bit. Like 901Memphis said, as long as it's between the Low/Full marks (or just a hair over), it'll be fine. For instance, on my Firebird it calls for 4.6 quarts, but I put in 4.5. My mom's old 2003 Malibu used to call for 4.6 also, and I'd use 5 quarts when using an oversized filter. If I used the regular sized filter, I'd use 4.5 quarts or so. I may end up doing the same in the Firebird if I continue to use oversized filters on it. It would usually bring it up to just a little bit above the full mark.
As long as you are in the cross hatch area you are fine. I like it to be to full line though, for peace of mind but your car wont miss it. My Accord calls for 4.5 quarts with filter. I used 5 quarts this previous OCI. Shows over the full mark and its fine.
I'm gonna be honest, when I change the oil on a car I've done before, I don't even check the dipstick. My grandmas Trailblazer gets 7 quarts, grandpas Cherokee gets 6, my old Chevy truck with a 350 got 5, and my Camry gets 4