comparison between point and integer

Question

Right, basically I want to add two numbers together. It's for a working hours calculator and I've included parameters for a night shift scenario as an if statement. However, it now mucks up the day shift pattern. So I want to sort out that if the start time is below 12, then it'll revert to the original equation shown in the code instead of the if statement.

-(IBAction)done:(id)sender {
    int result = [finishHours.text intValue] - [startHours.text intValue];
    totalHours.text = [NSString stringWithFormat:@"%d", result];
    if (result < 0) {
            totalHours.text = [NSString stringWithFormat:@"%d", result * -1];

    }
    if (result < 12) {
            totalHours.text = [NSString stringWithFormat:@"%d", result + 24];
    }
    if (startHours < 12) {
            totalHours.text = [NSString stringWithFormat:@"%d", result - 24];
    }