Return Values from PixeltoValue not consistent?

[User (Legacy)]

I am using the PixeltoValue method to capture the x-axis label position 

(first, second, third,etc.) that the mouse is hovering over. In each case, 

my x axis is categorical.  Sometimes PixeltoValue returns a value that 

rounds to 1 in the x value for the first label (continuing with 2,3,4, etc), 

other times it returns a value that rounds to 0 for the x value, continuing 

with 1,2,3,4,etc. 

Why is it that I am getting this inconsistency? Is there a property to 

adjust where the x-axis starts in chart coordinates ? 

Is there a different method of determining which label the mouse is hovering 

over on the x-axis that is consistent? 

I have attached a sample app with two .cht files. One will demonstrate the 

0-based behaviour and the other demonstrates the 1-based behaviour. Just 

load one of the two and hover the mouse over the x-axis labels. 

NOTE: I consistently get one or the other in the same chart file - for 

example, zero.cht ALWAYS starts its x-axis label position near 0, and 

one.cht  ALWAYS starts its x-axis label position near 1. That's why I 

thought maybe a property is inadvertently getting set in the chart file? 

Again, thanks for your help! 

Gretchen