Pointed Deciever x Withering Rot hybrid is not just "S+1", it is:
-1A, -1S
SUPPRESS A, x-1S

It's important you do not combine hybrid powder effects together in your head when using them in magic mud, because mud looks at all the mushrooms inside together. Hybrid powders do not combine the effects into one new effect, they list both mushroom effects together for a reason.

If you use two lots of this hybrid you're now doing:
-1A, -1S
SUPPRESS A, x-1S
-1A, -1S
SUPPRESS A, x-1S

Totalled up, you have:
-2A, SUPPRESS A, -2S, x-1S, x-1S
Taking the SUPPRESS into account, you now have:
-2S, x-1S, x-1S

-2, x-1 is +2, then x-1 AGAIN is -2
Which is what you're seeing in your second pic.

Same thing in your third picture, you're using 6 mushrooms, giving you the following effects:
-1A, -1S
SUPPRESS A, x-1S
-1A, -1S
SUPPRESS A, x-1S
MIN N
SUPPRESS A, x-1S

Totalled up, you have:
-2A, SUPPRESS A, -2S, x-1S, x-1S, x-1S
Taking the SUPPRESS into account, you now have:
-2S, x-1S, x-1S, x-1S

-2, x-1 is +2, then x-1 AGAIN is -2, then x-1 AGAIN is +2
Which is what you're seeing in your third pic.

I was looking for answers before posting a new thread so I think maybe here you were trying to get the Archive Pool frog? I'm super lost as to how to get -1A-1N-1O-3S