Setting ZipArchiveEntry.LastWriteTime loses precision by factor of seconds

Question

I'm trying to set the ZipArchiveEntry.LastWriteTime so that when extracted, it is the 'exact' same time, but I'm getting random time differences. Here is a specific example.

var fileName = @"C:\BTR\Publish\ESS\Test\RTX\Global.asax";
var sourceRoot = @"C:\BTR\Publish\ESS\Test\RTX"; // Want entry full name to start with RTX
var target = @"C:\BTR\Publish\LWT.Test.zip";

var lwt = File.GetLastWriteTime(fileName);
Console.WriteLine( $"File: {fileName}, Date {lwt:yyyy-MM-dd HH:mm:ss.ff}" );

using ( var fs = File.Create( target ) )
using (var stream = new ZipArchive(fs, ZipArchiveMode.Create))
using (var source = File.OpenRead(fileName))
{
    var rootLength = Path.GetDirectoryName(sourceRoot).Length;
    var entryName = fileName.Substring(rootLength + 1);

    var entry = stream.CreateEntry(entryName, CompressionLevel.Fastest);
    
    entry.LastWriteTime = lwt;
    Console.WriteLine( $"ZipArchiveEntry: {fileName}, File Date: {lwt:yyyy-MM-dd HH:mm:ss.ff}, Zip Date: {entry.LastWriteTime:yyyy-MM-dd HH:mm:ss.ff}" );
    
    using (var es = entry.Open())
    {
        source.CopyTo(es);
    }
}

DateTime zipLwt;

using (var fs = File.Open(target, FileMode.Open))
using (var zip = new ZipArchive(fs, ZipArchiveMode.Read))
{
    zipLwt = zip.Entries[ 0 ].LastWriteTime.DateTime;
    Console.WriteLine( $"Zip File Entry: {zip.Entries[0].FullName}: Date {zipLwt:yyyy-MM-dd HH:mm:ss.ff}" );
}

Console.WriteLine($"Date Difference: {(lwt - zipLwt).TotalMilliseconds}ms" );

This code outputs:

File: C:\BTR\Publish\ESS\Test\RTX\Global.asax, Date 2016-10-14 05:54:49.98 
ZipArchiveEntry: C:\BTR\Publish\ESS\Test\RTX\Global.asax, File Date: 2016-10-14 05:54:49.98, Zip Date: 2016-10-14 05:54:49.98
Zip File Entry: RTX\Global.asax: Date 2016-10-14 05:54:48.00 Date
Difference: 1989.243ms

Any ideas on how to make the dates exact? When I set the LastWriteTime it appears to be good according to the output, but when I extract it, it is wrong.