Ranked System needs to be Reworked

This system needs to be reworked badly, as is its harder to advance with in a division than it is to go from one division to another. And heres the math to prove it.

Going from S2 to S1 requires 2 out of 3 Whereas Going from S1 to G5 requires 3 out of 5

So very simple math shows that 2/3 = 66% win rate and 3/5 = 60% win rate.

And we can take this a step further and say that typically to even get into your series you have to win 2 games in a row, some times more

so then it becomes

S2 to S1 4 out of 5 4/5 = 80% win rate S1 to G5 5 out of 7 5/7 = 71% win rate

Why is it harder to go from S2 to S1 than it is from S1 to G5, it should be reversed. This is mathematically proven, and field tested. I kept track of how many times I lost my series going from S5 to G5 this season.

S5-S4 lost 2 series before winning S4-S3 lost 3 series before winning S3-S2 Lost 3 series before winning S2-S1 Lost 2 series before winning S1-G5 lost 1 series before winning.

So on average I lost 2.5 of my series before progressing while in S, where as getting from S to G I only lost 1 before progressing.

Is it really supposed to be harder to get from S5-S4 than it is from S1-G5?

My GF is another prime example of the bad system, she is trying to get to G5 this season to get the skin, and she is having alot of trouble because of this, she will win 2-3 games in a row get into her series an lose 2 of those 3 games, even tho she still sits at a 70+% win rate throughout her last 10 games she just can not progress though her series do to the unforgiving nature of the advancement though a said series.