The Question and Answer section for Arms and the Man is a great resource to ask questions, find answers, and discuss the novel.
Captain Bluntschli becomes the "chocolate cream soldier" because he carries chocolates rather than bullets. He has an aversion to killing and affection for sweets.
Sergius means that the Swiss fellow charged them too much for the horses. He took advantage of them.
Petkoff. What, that Swiss fellow? Sergius: I’ve often thought of that exchange since. He over-reached us about those horses.
Sergius. Of course...
What extract are you referring to? What act is this in?