Markal 96823 Valve Action Paint Marker, Black

I used an older pen i had for years that lasted for years, with great valve action and nice, gloss paint. Bought 2 replacements since then. Valve action is lousy, or else the amount of paint in the pen is miniscule. The finish is dull to flat and, shake it as I might, the paint doesnt seem to mix well. Customer service less than helpful, saying only to look at the MSDS for information. True, I'm not using it to mark bars of metal or in a factory for materials, but in my art projects, but I was hoping for product consistency and quality of my original marker.