True..Its totally random and based on players observation over time we have fixed certain values like around 60 you will get a rare as in kage treasure. I dont think that this has been officially mentioned by OAS anywhere that you would be getting in so many pulls, but we all know from practice. If a meter is put and people are not getting around this value, then people would come around complaining that its a bug , blah blah and blah. People already put such threads in forum, so it will even get worse with introdction of a meter. You cant blame anyone because its just the anticipation for a new ninja that just drives us over the edge. Therefore to avoid such unwanted complications they might not be creating a meter. Just what I think about this meter thing. Personally I think it would be cool to have it since I dont have to keep mental calculations to remember how many seals i have spent.