Different NSDate for same timestapm on ios versions (ios 6 and iOS7) - objective-c

Question

I ran into this weird issue where one of the method in my code is returning different dates for same timestamp value in different ios version.
Following is the code for that method.
+(NSDate *)getDateFromTheTimeStampAsDate:(NSInteger)timeStamp
{
NSLog(#"Timestamp - %d",timeStamp);
NSDateFormatter *dateFormatter=[[NSDateFormatter alloc] init];
NSLocale *usLocale = [[NSLocale alloc] initWithLocaleIdentifier:#"en_US"];
[dateFormatter setLocale:usLocale];
[dateFormatter setTimeZone:[NSTimeZone timeZoneWithName:#"PST"]];
[dateFormatter setDateFormat:#"MMM DD,yyyy"];
return [dateFormatter dateFromString:[dateFormatter stringFromDate:[NSDate dateWithTimeIntervalSince1970:timeStamp]]];
}
For timestamp = 1361581013 following are the NSDates values returned from above function:
iOS6 - 2013/02/01
iOS7 - 2013/02/22
Is there anything wrong with this code ?
Update: I forgot to look at the date format, earlier. Thanks to one of the comment I managed to get correct date. This was a part of legacy code so in the decided to just trash it and use following:
[NSDate dateWithTimeIntervalSince1970:timeStamp];

Answer 1

First the output isn't ever close to the date. On the terminal try date -r 1361581013. At least then you can see if you are getting close.
Second, convert the timestamp to an NSDate. Log that see if its close.
NSDate *d = [NSDate dateWithTimeIntervalSince1970:1361581013] ;
NSLog(#"d = %#" , d) ;
Third after you know you are getting the NSDate then apply formats to it.
NSDateFormatter *df = [[NSDateFormatter alloc] init];
df.dateStyle = NSDateFormatterLongStyle;
df.timeStyle = NSDateFormatterLongStyle;
df.timeZone = [NSTimeZone timeZoneWithAbbreviation:#"PST" ];
NSLog(#"d with formatting 1 = %#" , [df stringFromDate:d]) ;
df.timeZone = [NSTimeZone timeZoneWithAbbreviation:#"EST" ];
NSLog(#"d with formatting 1 = %#" , [df stringFromDate:d]) ;
df.timeZone = [NSTimeZone timeZoneWithAbbreviation:#"GMT" ];
NSLog(#"d with formatting 1 = %#" , [df stringFromDate:d]) ;
Then you will know you got it right.
d = 2013-02-23 00:56:53 +0000
d with formatting 1 = February 22, 2013 at 4:56:53 PM PST
d with formatting 1 = February 22, 2013 at 7:56:53 PM EST
d with formatting 1 = February 23, 2013 at 12:56:53 AM GMT