PredX returns values outside of data range

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I'm using the App Statistics 2Var to do a quadratic fitting to the following data:

C1: 1, 1.05, 1.1, 1.14, 1.16
C2: 68, 67.2, 62.8, 59.1, 54.7

Once the fitting is done, using PredX and PredY in HOME I get:

PredY(1.1) -> 63.3070360465 OK
PredX(63.3070360465) -> 0.9 ??? I expected 1.1

After some investigation I realized that the fitting parabola is symmetrical with respect a vertical axis at x=1, so PredY(0.9)=PredY(1.1)=63.3070360465, and mathematically both PredX(63.3070360465)=0.9 and PredX(63.3070360465)=1.1 are correct solutions.

Perhaps in cases like this, when PredX has more than one solution, the calculator should favor a value that is inside the data range (1.1 in this case), instead of returning the first solution found (0.9 in this case).