EDIT: You are correct thought it said opens up at the end of the month of each season.

I had gained over 600 coupons from the drawing, frankly, I like it, but unfortunately, its a waste to spend coupons to spend coupons on the tickets. Though, I did gain 40 adv refines....which are priced cheaper than the tickets. But you do you, I personally won't spend coupons on them.

You could propably get somewhere between <450 tickets + bonus from top ranking (max of 50) throughout the season. Looking at the table above frags have 5% drop rate and more or less thats my result as well. I already 4* shira without using tickets (not recruited han, no top1 ST/zenith medal either). Unless you aim for top1 ranking spot and want a chance to 5* certain ninja (and we have no idea who will be there, but lets be real dont expect godtier ninjas) in which case those ~25frags might make a difference, otherwise its honestly pointless to save those tickets. If you play, youll get enough frags to 4* seasonal ninja, without considering ranking reward anyway.