Thread: if loop only goes through once

Hey guys! I'm writing a program that reads a starting time and an ending time for delivery that it normally takes. There is construction with a 25% delay on deliveries. The program must take the two times entered, incorporate the 25 percent delay and output the new ending time.
It reads times using a 24 hour time period (so 2345, 0615, etc.) converts the time to minutes by multiplying by .6. But if I try to divide by .6 to put it back into hour time, it goes to base 10 not base 60 so it comes up with times like 0697. So I made an if loop to figure out number of hours and then the left over put into minutes. Anyway, my problem is the if loop only goes through once. Any way you can see why it's doing this? (P.S. I'm pretty proficient in C++ and C# is a new language for a class in college, so I understand terms pretty well)

Code:

using System;

class Program
{
    static void Main(string[] args)
    {
        Double _startTimeMinutes, _endTimeMinutes, _totalTime, _timeAddedMinutes, _percent, _newEndTimeMinutes, _startTime, _endTime;
        _percent = .25;
        int _hour = 0;

        Console.WriteLine("Please input the start time in 24 hour mode (no colon or decimals): ");
        _startTime = int.Parse(Console.ReadLine());
        Console.WriteLine("Please input the end time in 24 hour mode (no colon or decimals): ");
        _endTime = int.Parse(Console.ReadLine());
        _startTimeMinutes = _startTime * .6;
        _endTimeMinutes = _endTime * .6;
        _totalTime = _endTimeMinutes - _startTimeMinutes;
        _timeAddedMinutes = _totalTime * _percent;
        _newEndTimeMinutes = _timeAddedMinutes + _endTimeMinutes;
        
        Double _newEndTime = _newEndTimeMinutes;
        if (_newEndTime > 60)
        {
            _newEndTime = _newEndTimeMinutes - 60;
            _hour++;
        }
       char _space = ' ';
        if (_hour < 10)
        {
            _space = ' ';
        }
        else { _space = '0'; }
        Console.WriteLine("New end time because of construction is: {0}{1}:{2}",_space, _hour, _newEndTime);

        Console.ReadLine();
        
    }
}