Why is the instruction so poor?

It seems like an attempt to be thorough,
but it's just poor instruction repeated for pages and pages
in what could have been communicated in 1 page.

On top of that, I'll give an example of poor instruction.
This won't give away any secrets, but here's an example of something very near to what you'd read in Isabella's Star:
To work out an Astrological Number, take the date and ___ it and ___ the month number. (I had to figure out that by "date" meant day of the month...maybe this is a british thing). For example, if the date is the 3rd of March, take the day (in our case 3), ___ it, and ___ the month number.
In our case it's the 3rd month, so the total would be __. Then take the year, for 2003, in our case, the year would be 3. So take 3, then ___ 3, and then _____ by 3.

??

Why would you use the same digit for explanatory purposes?
That was Isabella's Star 1. Did they improve the explanation in 2? No, they made it even more hard to understand. In IS2, they used May 5th, 2005 as the example. So you have to follow along their explanation, "So all you do if the date is 5, 05, 2005, is first take 5, then __ it by 5, next ___ 5 and you get ___, then all you do is ___ 5 to the total."

The above is my first frustration with IS2 (just making the same teaching mistake as he did in IS1).
I had to read the explanation 10 times to try to figure out what he was talking about; it could have been written so much better.

What about the end effect? In the end, that's what matters.
In short, it doesn't quite match what you'd expect from the description. You don't just walk up to someone and know their sign.

Without revealing any method, a more honest description of the effect would be:
Imagine walking up to a complete stranger in the park. You teach them a lecture on how to calculate a number based on their date of birth. Then you pull out a deck of cards to help them find their date of birth as it would correspond to a deck of playing cards. Alternatively, you could have them write down something. Then after just one or a few guesses, you tell them their date of birth!

Basically, it would be like a magician who can just classic force a card, or control a freely chosen card effortlessly...and then that magician arrives at the chosen card by dealing 3 columns of 7 rows of cards, asking the spec whether her card is is such and such pile, then dealing another 3 rows of 7 rows of cards, and on and on and on.... just to find a card.

So the magician could've forced a card in 10 seconds (CT or peek), or he can find the card using the 21 card method in only 2 and a half minutes.

I'm gonna stick with a CT. Using any CT or peek, which you can purchase instructions for on penguinmagic, you can tell them their date of birth (without any pre-show!, lol). the method itself will demand less from the spectator (they won't need to calculate something, then write something down or use a deck of playing cards), and getting to the climax will be faster.

Or, you could do what I do. And just say something like this, "You know, you seem like a Leo (most common sign..watch reaction)...but a Virgo (next most common sign) would be better for this next trick." Now you've got about a 1 in 5 chance of being right. A miracle!!! (for one in every 5 shows...the other 4 shows nobody remembers that you tried to guess their sign).

This effect is great and i hope Peter keeps the price this high. I really recommend it if you wanna improve your mentalism set. Is a really powerful piece.

Isabella's star is a beutiful routine wich if you know the method will certainly agree i mean to reavel when the spectator was born is one of the greatest pieces of mentalism you can preform and now you get another way of preforming without the math and memory work of the previous routine with the addition of having there zodiac signs revealed as a double kicker oh yeah and theres no more progressive anagram so now it's a routine that's much easier same power and an extra kicker so what are you waiting for?buy it now