Seriously, you might try some different mouthpieces with the horn and see if that helps. While there are always exceptions, I've found these horns to be pretty good. Also, it has been my experience that there are very few notes on a horn that can't be adjusted with slide manipulation or alternate fingerings, especially one like the 995 that has 5 valves. It will all depend on how much you like the horn's other characteristics to decide if you're willing to put up with the extra work to deal with the intonation if you can't find a solution with a different mouthpiece. Best of luck to you!
My opinion for what it's worth..