The S-rank pity is 20 pull and at that point you'll receive 80% chance of CUB that you targeted.
But the main % for S rank (before pity) is too high. 8% is like guaranteed 1 for 10 pull and the one you get is random.
Imagine, you want Dawn Chorus, you targeted it, then you save up 20 tickets for it. After you do 10x spin, you got a stupid S-rank squid and your pity reset to 0/20 instead of 10/20 which you missed your 80% chance to get your Dawn Chorus. So what's the use of 80% chance?
It is harder to get the one you CHOOSE (to reach 20x without even a single S-rank) rather than to get random S-rank with 8% chance.
DECREASE THE MAIN % FOR S-RANK CUB SO YOUR 80% FEATURE CHANCE IS MORE USEFULL