questions about PONG message

I collect some PONG messages from LimeWare, analyze them and find some 
question:

1. I use PingReply.getFiles() to get the number of files shared and use 
getKbytes() to get the number of kilobytes shared. In some messages, 
num_shared_files=0, but num_shared_kbytes¡Ù0, I don't know why?

2. I don't get the exact meaning about  getNumLeafSlots() and 
getNumUltrapeerSlots().  The NumLeafSlots mean that the remote host has 
connected some LeafPeers or will accept some LeafPeers?

Thanks!!!