I have the following code
(...) numberStyle = [NSDecimalNumberHandler decimalNumberHandlerWithRoundingMode:NSRoundPlain
Why not use textFieldThree.text=[NSString stringWithFormat:@"%.2f",[fieldOneDN floatvalue]];
textFieldThree.text=[NSString stringWithFormat:@"%.2f",[fieldOneDN floatvalue]];
(or something similar - sorry I'm on a PC right now so can't test this)