Upscale audio advice

I have been looking to change the tubes on my BAT VK-30 from the Russian made 6922/6h23 which work fine but am looking into upgrading them. I looked at the Upscale selection and a few options initially caught my eye. These are as follows:
1)Amperex 7308 vintage gold pin
2)Amperex 6DJ8/ECC88 Bugle Boy
3)Ediswan CV2492/6922
4)Mullard 2493/6922 & Mullard E188CC/7308

All of which, if I choose their Platinum grade, range from $70 to $110.00 each which seemed pretty reasonable to me. The problem is, their sales guys tells me that none of these are suitable for my Pre-amp. He goes on to tell me that the only units that will work are the very same 6H23's that I already have. Is this sound advice from them given the fact that I would like to spend some decent coin to upgrade or do they not wish to deal with me? I have seen in other forums that they tend to want to sell to customers who have purchased equipment from them. Is this true? I do want to change my tubes given the fact that they are about 5 yrs old and definately are due for a change. I find it hard to believe that the only option they have that will work with my VK-30 would be these cheaper $35.00 per tube units. Any further comments anybody may want to add to this or advice you may have for me?
Samhar, Here is Upscale's page concerning the 6922 family of tubes. As I said, the 7DJ8s are working fine in my preamp and have been for the past 5 months. Dick
Thanks Dick interesting info !!!
I dealt with upscale audio on NOS 6922's for a BAT phonostage. At first, Kevin recommended the Amperex 7308. As these were going to cost $100.00 each I decided to wait. After a few months, I contacted Kevin again about the 6922's and mentioned that he had previously recommended the Amperex tube. I Asked if they were still his "personal Fav." He told me they were but not in BAT equipment. Recommended the Ediswan 2492. I bought 4 of them. They did not work out for me. I had two go bad right away. I think he called it "microphonic." Anyway, I sent the tubes back and he replaced two of them. Long story short, these tubes did not improve the sound and in fact never really worked that well. I went back to new production Sovtec's.

Kevin was real good to deal with but I think that the BAT equipment is very sensitive to what tubes it likes and Kevin kinda realized that. Sounds like he is getting totally away from recommending NOS for BAT stuff. I would take his word for it. It has been my experience that Bat and NOS don't mix.
Can't swear to how hard the BAT pre's run their tubes, BUT- I've had the same six early 60's, Siemens CCa's in my VK-D5, for over five years(they were NOS), without a single problem.
Just for an update I have tried 6 Holland made BUGLE BOYS. They sound very good compared to the 6h23's that they replaced. So that answers one question is that I can use more than the Russian made tubes as I was told a few months back. Hope they last more than 2 weeks though.
I had questions on mixing tubes on a thread I started last night.