PinchGestureUpdatedEventArgs Scale not working as descripbed in the API doc

I am working with Xamarin.Forms.PinchGestureUpdatedEventArgs.Scale Property, and found it's not working as described in the API document. Here is the description from the doc.
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The relative size of the user's pinch gesture.
Syntax
public Double Scale { get; }
Value

The distance between the user's digits, divided by the initial distance between the user's digits in the pinch gesture.

Remarks:

This initial value of the PinchGestureUpdatedEventArgs.Scale property for each new pinch gesture is 1.0

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I did a testing program, which keeps showing the Scale value in the event handler. When my two fingers have already moved far apart from the initial positon, such as 3 times the original distance, the Scale value is still just a little bit more than 1, something like 1.01, 1.02

So my question is what exactly this Scale value is. Since mostly it's 1.xxxx (or 0.9xxx) , my guess is that it might be "The distance between the user's fingers divided by the distance reported in last update event....?"

Also, the value could somehow suddenly drop to 0.5xxxx even if I am doing "enlarge"

Can someone shed some light here?

Thanks.