The film was not expired. Was kept in freezer since I bought it also. Since I import them, v $$ here where I am.
I shot them with and without the filter of the two frames and adjusted the stops. Tried it on my dxxxxxx too. Same with some of the folks on flickr.
I am thinking about maybe not using solid NDs now. Hitech grads IME is quite neutral. Not the same as if you taken two shots with film and do a blend in software. Not that neutral, IMO the Hitech grad enhances the sky in not a bad way. Not sure if there is such as as a perfectly neutral filter. Maybe shoot when the water is calm and some may argue that long exposures blurs the water that might not be so appealing as a pristine calm lake / water. Then again I cannot blur angry fast moving water. I could resort to round filters that I have already but cannot use grads. Ie., 2 stop B+W which is not perfectly neutral but very neutral and maybe also a C-Pol and stop down the aperture to the extreme. I find my 6 stop B+W does get a magenta cast not as bad as Hitech but B+W confirmed their website's advice that is use a hot mirror after I sent them some pictures.