Ovals changing size [JS CS4]

Question

I create an oval and set it to be 10 inches in diameter as follows:
var thisDoc = app.documents.add();
thisDoc.documentPreferences.pageHeight = "11i";
thisDoc.documentPreferences.pageWidth = "11i";
thisDoc.documentPreferences.pageOrientation = PageOrientation.landscape;
thisDoc.documentPreferences.facingPages = false;
var thisPage = thisDoc.pages[0];
var inputValue = 100;
var valueToInches = inputValue * 0.05;  // 5
var circleXY = 5 - valueToInches;  // 5 - 5 = 0.5
var circleWH = 2 * valueToInches;  // 2 * 5 = 10
var useXY = circleXY + "i";  // specifying number in inches
var useWH = circleWH + "i";
var myCircle = thisPage.ovals.add({geometricBounds:[useXY, useXY, useWH, useWH]});
//  top left placed at 0, 0        -- as expected
// resulting circle is 10 x 10 in. -- as expected
When I offset it to center it on the page, the oval is created 0.5 inches smaller:
var thisDoc = app.documents.add();
thisDoc.documentPreferences.pageHeight = "11i";
thisDoc.documentPreferences.pageWidth = "11i";
thisDoc.documentPreferences.pageOrientation = PageOrientation.landscape;
thisDoc.documentPreferences.facingPages = false;
var thisPage = thisDoc.pages[0];
var inputValue = 100;
var valueToInches = inputValue * 0.05;  // 5
var circleXY = 5.5 - valueToInches;  // 5.5 - 5 = 0.5
var circleWH = 2 * valueToInches;    // 2 * 5 = 10
// specifying number in inches
var useXY = circleXY + "i";
var useWH = circleWH + "i";
// debug:
$.writeln(circleXY);  // "0.5"
$.writeln(circleWH);  // "10"
$.writeln(useXY);     // "0.5i"
$.writeln(useWH);     // "10i"
var myCircle = thisPage.ovals.add({geometricBounds:[useXY, useXY, useWH, useWH]});
//  top left placed at 0.5, 0.5      -- as expected
// resulting circle is 9.5 x 9.5 in. -- not expected
Perplexing. Any clues as to what I'm obviously doing wrong here?

Answer 1

Ovals, like all other objects, are not specified by [ x,y, width, height ].
The correct order in GeometricBounds is
[ topy, leftx, bottomy, rightx ]
-- you can simply add your width to your left x and your height to your top y to get the right numbers.