C#调用顶尖PBUSDRV.DLL时，如果保质期shleftime大于3时，下传就报错

结构体声明如下：

[StructLayout(LayoutKind.Sequential, CharSet = CharSet.Ansi)]
public struct TPlu
{
//[MarshalAsAttribute(UnmanagedType.ByValTStr, SizeConst = 36)]
public string Name;
public int LFCode;
//[MarshalAsAttribute(UnmanagedType.ByValTStr, SizeConst = 10)]
public string code;
public int barcode;

        public int unitprice;
        public int weightunit;
        public int deptment;
        public double tare;

        public int shleftime;

        public int packagetype;
        public int packageweight;
        public int tolerance;
        //[MarshalAsAttribute(UnmanagedType.ByValTStr, SizeConst = 1)]
        public byte message1;

        //[MarshalAsAttribute(UnmanagedType.ByValTStr, SizeConst = 1)]
        public byte reserved;
        public short reserved1;
        //[MarshalAsAttribute(UnmanagedType.ByValTStr, SizeConst = 1)]
        public byte message2;
        public byte reserved2;

        //[MarshalAsAttribute(UnmanagedType.ByValTStr, SizeConst = 1)]
        public byte multilabel;
        //[MarshalAsAttribute(UnmanagedType.ByValTStr, SizeConst = 1)]
        public byte rebate;
        public int account;
    }

其它INT型的参数都一切正常，唯独shleftime大于3时，下传就报错。0-3下传正常。是否要特殊处理？
文档对于保存期shleftime的说明：宽度 3，默认 15，描述：0~365, 其中 364: 不打印有效期; 365: 有效期和包
装日期均不打印包装日期为零时,包装日期及保鲜日
期均打印。

然而同样写的PB,VB程序则正常。

贴出你所谓正常的VB代码，我可以帮你看看。