Well that's just a bit of math.

When you're paralyzed, you will have a 75% chance to act at all.

A Serene Grace Togekiss using Air Slash will have a (30x2) 60% chance to make you flinch.

So, in the start of the turn, Togekiss uses Air Slash, and on your turn:

If my calculations are correct:

Paralysis will allow you only a 75% chance to act, and within that 75% chance to act is a 40% chance to act.

I created a tree diagram: (0 = No action / ☆ = Action)

Paralysis:

0 ☆ ☆ ☆

Air Slash: (simplified)

0 : 0 0 0 0 0 0 0 0 0 0

☆ : 0 0 0 0 0 0 ☆ ☆ ☆ ☆

☆ : 0 0 0 0 0 0 ☆ ☆ ☆ ☆

☆ : 0 0 0 0 0 0 ☆ ☆ ☆ ☆

Basically each branch is the possibility from the Paralysis.

There is a total of 40 paths (simplified), and a total of 12 places where you are able to act based on probability.

So it will be a 12/40 chance to act, or simplified 3/10.

You will have a **30%** to act, assuming you don't get KO'ed, you are still slower than the Togekiss, and that no priority moves are being used.

This may be incorrect, but l am sure it isn't.