For the record, I am nothing great when it comes to putting. :(
But as far as elevation -/+ inches, something to consider is how gradual that elevation is or isn't.
What I think I am meaning to say... lol is, even though it may show uphill 6 inches ( just an example) at which point in the putts line does it start to elevate? OR, is there any point in the line that has a decline before it goes uphill.
I like to drag the aim arrow from ball to cup on my intended line to see if it is a gradual elevation change or partly flat and then jumps up a few inches.
To me, that is why a 15 foot putt uphill 5 inches may go long or short on another 15ft putt uphill 5 inches on a different green, or heck, even the same green but from a different part of the green.