Lots of people are willing to play expert on what to include in a synopsis, how long it should be, and the approach. I got a lot of advice on this early in my writing career (fiction, that is). One half of the advice directly contradicts the other half and authors will wrangle over which of the opposing advice is more correct than the other. Agents supposedly know all this stuff, but they're as bad as the amateurs in guessing what a synopsis should be.
Here are some rules to follow:
1. If an agent or publishers says they want a 100-page synopsis written in second person passive voice, you should probably skip them for querying.
What sounds ridiculous probably is. If an agent/publisher doesn't know enough to suggest some stupid things, then they're too stupid to sell your book. Sometimes agents place a high value on themselves which may not be shared by the rest of the world. That tends to make them feel (like politicians) they are above "the law" and any vague rules don't apply to them. Besides, they want to make sure you put in a lot of wasted time following their absurd rules to give them their power rush of the day. Don't bother.
2. If a writer has not yet published anything, whatever they say is probably wrong. There's a reason why they haven't been published and it might just be they don't know what they're talking about.
3. A query letter should be less than one page long (if printed). It is not a synopsis.
3. The length of a synopsis is not directly proportional to the length of the work. Keep it short.
4. Say how the story ends. This is not a teaser or blurb; it's the story in a nutshell.
5. Pay no attention to any of this advice.
Teddy says if he can't understand your synopsis, then it's too complicated. Happy Querying!