It seems that Tixati is not calculating the upload ratio based on the amount of data downloaded but the total size of the local files.
Please refer to this screenshot:
http://postimg.org/image/h8aoimeyj/
On that screenshot Tixati shows that 444 MiB of File Data were downloaded and 837 MiB uploaded, so the ratio should be 1.885, however, the calculated ratio is 0.183.
On that torrent, i have 4.46 GB of completed files ( 837 MiB / 4,567 MiB = 0.1832712940661266 Ratio )
Usually you wouldn't notice that behaviour, but in my case: A new torrent is released each week, with one extra file appended to the previous ones ( they do this to keep previous files available ) but this makes seeding to a fixed ratio really unfair for some of us. ( on this scenario, it would have to upload 6.69 GiB to reach the 1.5 ratio for the 444 MiB i downloaded instead of the 666 MiB it should be... Way too much, don't you think?)