Do you guys think I'm losing seriously in my sales volume b/c I'm located in Russia?
No, in short.
I personally have never encountered this kind of a problem. Ever.
Having most of the names with Russian registrant address.
Including sold ones...
Most of the time your prospective buyers dont even know how to use whois.
And when they do that's the last thing they would care about, especially if the name is regged with a reputable US/Europe based registrar. According to my experience.
When they want the name they would buy it from you even if you are from Nigeria (well, if they can afford the price you put on it, that's what matters most)
High percentage of backing out clients is probably a problem of contacting wrong people - when you do outbound your initial contact almost always is not a decision maker.
So he just says "we could be interested" (which is not binding) and requests more info, then passes it up to the right person who often replies with "we just don't need this stuff. we already have one we regged for $15 some 500 years ago, why have two?"... at this point they stop communicating or tell you "thanks, we decided we are not interested" at best, leaving you guessing if it was your country of residence or a tie color that ruined the deal. No, the deal was not going to materialize from its very beginning... no one cares where you live.
Inbound requests, in contrast, are always made by/on behalf of a decision maker so you can be sure it's backed by real interest behind it, not just "looks interesting, tell me more, i'll ask my boss"..
Additionally, if you have to use outbound mailing we are talking of lower quality names, as a rule. Those do have much higher rate of not closed sales simply because when buyers at some point realize how much time and effort they need to spend (payments, escrows, transfers etc) on a not so needed $1xx name - not worth it, not a killer name anyway...
just my non-binding imho...