Regarding the transaction proposed by the Russians, Chen Yu was indeed interested, but the Russians offered something unequal to what they would receive, so Chen Yu needed them to present something to truly persuade him.
However, asking the Russians to re-quote requires some skill. Chen Yu couldn't directly tell the Russians that their offer was too low and he was unsatisfied.
This kind of wording, while not impossible, is too blunt and can easily turn what could be a sentiment of gratitude into the Russians thinking they have paid for it with hard money and no longer need to owe Chen Yu favors.
Out of consideration for this, the best way for Chen Yu to get the Russians to re-quote naturally involves hinting through some means, making the Russians understand that their offer was too low.
Treating Andrei is a great opportunity for a hint. While Chen Yu's approach isn't drastically different from making it explicit, it still beats directly telling the Russians to re-quote.
