setUTCx group of methods of QML's Date object works strange

In an example function (which you can see below) I use hadwritten parsing of string representation of current datetime. If I use current time (which can be obtained by new Date()) as "stamp" (look at code), parse it and use set of setUTCx functions of Date object to set correct values I'll get absolutely wrong date, which sometimes differ about 2 days from original. Here is an example output in Qt Creator:

— Sat, 2014 Apr 19 7 11 27
— Sat Apr 19 11:34:53 2014 GMT+0400
— Sat Apr 19 11:34:53 2014 GMT+0400
— Sat Apr 19 07:34:53 2014 GMT+0400 // Whoops: -4 hours
— Sat Apr 19 03:34:53 2014 GMT+0400
— Sat Apr 18 07:34:53 2014 GMT+0400 // Day changed 0_0
— Sat Apr 18 03:11:53 2014 GMT+0400
— Sat Apr 17 23:11:27 2014 GMT+0400

Output in chrome (the same code works fine)

— Sat, 2014 Apr 19 7 11 27
— Sat Apr 19 2014 11:12:23 GMT+0400 (MSK)
— Sat Apr 19 2014 11:12:23 GMT+0400 (MSK)
— Sat Apr 19 2014 11:12:23 GMT+0400 (MSK)
— Sat Apr 19 2014 11:12:23 GMT+0400 (MSK)
— Sat Apr 19 2014 11:12:23 GMT+0400 (MSK)
— Sat Apr 19 2014 11:11:23 GMT+0400 (MSK)
— Sat Apr 19 2014 11:11:27 GMT+0400 (MSK)

Example function:

function testTime() {
var stamp = "Sat, 19 Apr 2014 07:11:27 UTC" // Use current date time here
var parts = stamp.split(" ");
var dayName;
var monthName;
var day;
var time;
var hours;
var minutes;
var seconds;
var year;

dayName = parts[0];
day = parseInt(parts[1], 10);
monthName = parts[2];
year = parseInt(parts[3], 10);
time = parts[4].split(":");
hours = parseInt(time[0], 10);
minutes = parseInt(time[1], 10);
seconds = parseInt(time[2], 10);

var month = 0;
if(monthName=="Jan")

{ month = 0; }

else if(monthName=="Feb")

{ month = 1; }

else if(monthName=="Mar")

{ month = 2; }

else if(monthName=="Apr")

{ month = 3; }

else if(monthName=="May")

{ month = 4; }

else if(monthName=="Jun")

{ month = 5; }

else if(monthName=="Jul")

{ month = 6; }

else if(monthName=="Aug")

{ month = 7; }

else if(monthName=="Sep")

{ month = 8; }

else if(monthName=="Oct")

{ month = 9; }

else if(monthName=="Nov")

{ month = 10; }

else if(monthName=="Dec")

{ month = 11; }

console.log(" — ", dayName, year, monthName, day, hours, minutes, seconds )

var dt = new Date();
console.log(" — ", dt)
dt.setYear(year);
console.log(" — ", dt)
dt.setUTCMonth(month);
console.log(" — ", dt)
dt.setUTCDate(day);
console.log(" — ", dt)
dt.setUTCHours(hours);
console.log(" — ", dt)
dt.setUTCMinutes(minutes);
console.log(" — ", dt)
dt.setUTCSeconds(seconds);
console.log(" — ", dt)
}