I realized first the number of downloads reported usually by trackers is never shown in Tixati (for all the trackers i tried so far).
Then i found that even the number of seeders and peers is not shown for some, for example with a private tracker (not all), Tixati after connecting with it only give this message "OK TTL xx:xx:xx" , in other trackers the message looks like "Ok Seeds=XX Peers=XX TTL xx:xx:xx" , by the way those info from the mentioned tracker are shown correctly by utorrent.

I don't know very well specifics of this but I guess some trackers when answering don't tell numbers of seeds and peers tracked for a torrent in fields provided. Also some trackers can answer false numbers like zeros however they do return some IP addresses. In that case Tixati won't show appropriate numbers next to tracker response.

You can check how many IP addresses were returned in en event log of a transfer. These are only addresses provided to you, not all tracked IPs.