Fast Casting in response to your own actions

The page 173 quote is the one I was referring to

The sentence

"Thus, a magus can not cast more than one normal
spell, or a fast cast and a normal spell in the same
round."

should be read as:

Thus, a magus can not cast:
A) more than one normal spell,
or
B) a fast cast and a normal spell in the same round.

Here's the link to the previous discussion