public class DapListComparer : IEqualityComparer<DeviceAccessPoint>
{
    public bool Equals(DeviceAccessPoint x, DeviceAccessPoint y)
    {

        if (x == null || y == null) return false;

        if (x.OrderNumber != y.OrderNumber)
            return false;

        //UseableModuleId null checks
        {
            if (x.UseableModuleIds == null && y.UseableModuleIds == null)
            {

            }
            else
            {
                if (x.UseableModuleIds == null || y.UseableModuleIds == null)
                    return false;
                if (x.UseableModuleIds.Except(y.UseableModuleIds).Any())
                    return false;
            }

        }

        //UseableSubModuleId null checks
        {
            if (x.UseableSubmoduleIds == null && y.UseableSubmoduleIds == null)
            {

            }
            else
            {
                if (x.UseableSubmoduleIds == null || y.UseableSubmoduleIds == null)
                    return false;
                if (x.UseableSubmoduleIds.Except(y.UseableSubmoduleIds).Any())
                    return false;
            }
        }

        if (x.DapId != y.DapId)
            return false;
        if (x.ModuleIdentNumber != y.ModuleIdentNumber)
            return false;
        if (x.SoftwareRelease != y.SoftwareRelease)
            return false;
        return true;
    }

    public int GetHashCode(DeviceAccessPoint obj)
    {
        if (obj == null)
        {
            throw new ArgumentNullException("obj");
        }
        unchecked
        {
            int hashCode = (obj.DapId + obj.ModuleIdentNumber + obj.OrderNumber).GetHashCode();
            hashCode = (hashCode * 397) ^ obj.OrderNumber.GetHashCode();
            return hashCode;
        }
    }
}

var dapListExceptance = appProcesses[0].DapList.Except(appProcesses[1].DapList, new DapListComparer());