Conditional formatting precedence question

Hi
I have an issue with conditional formatting precedence.
In cell C1758, I have an excel formula which returned - for this particular instance - “SF7”.
I am trying to highlight the cell with conditional formatting depending on the last digit.
So, with conditional formatting I use a formula with RIGHT and LEN function to extract the last digit ("7" in this particular instance) and compare it will specific values.

The following conditional formatting is done with cell C1758, in order of precedence:

1) Formula: = RIGHT (C1758,LEN(C1758)-2)>13 Format red color
2) Formula: = RIGHT (C1758,LEN(C1758)-2)>9 Format orange color
3) Formula: = RIGHT (C1758,LEN(C1758)-2)>0 Format yellow color

Because in this particular instance, the formula in cell C1758 returns “SF7”, the last digit “7” cannot fulfill conditions (1) and (2), therefore the conditional formatting should highlight the cell in yellow color.
However, for some reason not understandable to me, the cell was highlighted in red color.

Any advice on what could be the problem.
I am enclosing a snapshot of the conditional formatting for reference.

Thank you !!
It seems to work well.
For my learning purpose, may I ask what do the "--" before RIGHT function do?

Thanks again Sir!