In NavComHandlers.cs



 protected virtual string AddDefaultPattern(string value)
 {
     if (value.Length < MinPattern.Length)
     {

         value += MinPattern.Substring(value.Length);
    
         // This IFTHEN looks to see if it's a VHF COM freq (6 digits), and if the 10kHz position is either a 2 or 7.
         // Using 25kHz frequency spacing, freqs can only end with a .x25 or a .x75. This changes the .xx0 to .xx5 in
         // these cases. This is only an issue when verbally issued a frequency change by ATC where, in 25kHz spacing, they can
         // leave off the 5 (last digit).

         // In 8.33 kHz spacing, ATC is required to read all 6 digits, so a user would enter all 6 digits, and wouldn't
         // enter in this loop due to the parent pattern length matching IFTHEN.

         if (value.Length == 6 && ((value[4].ToString() == "2") || (value[4].ToString() == "7")))

         {
            string tempfreq = value.Remove(value.Length - 1, 1); // Strip the final 0
            value = tempfreq + "5"; // Append 5 as final digit to conform to 25kHz spacing
         }

     }

     return value;
 }