i think you are a little confused, the reversal point for the crab HAS to be at the 1.618 XA extension. lets say for example the BC is 2.24 - 3.618 and falls near to the 1.000 XA, lets say also an AB = CD falls on this area too, THIS IS NOT a crab as the reversal point for a crab is is 1.618 XA.
In that case it is not a crab, but as the AB = CD line up with the 1.000 XA [100% fib level] a profitable trade still might be possible as when a fib point along the XA leg converges with an AB = CD [or AB = CD extension (1.272, 1.618 …etc)] then price often reacts when it lands on this point if wing symmetry is good. good wing symettry = the angle of the move from A to B and the angle of the move from C to D is similar.
with a crab, the 1.618 XA and an AB = CD move (or extension) and a BC extension MUST ALL land relatively close to each other for it to be a crab.
[B]edit: [/B]I just checked. it appears that the AB = CD move does not have to fall massively close to the 1.618 for it to be a valid crab, but price MUST pass this AB = CD on the way to the crab or touch this level around the crab area. also a standard ab =cd is not that common in the crab, more common in crabsis an ab =cd extension
tbh, the crab is a tricky pattern. I do not see it all that often but when i see a suspected crab i first look in my book the harmonic trader volume 1 to see if the ratios i am seeing on screen are correct. the book is by scott m carney [the guy who invented the crab pattern and also a few others]
as for the babypips school on pattens, the babypips school section on these patterns are extremely brief and not in depth and lacks real world examples, therefore imo it is not a good place to learn about these patterns if you are a serious trader. I would have to reccomend the book i have if you are serious about it, it is clear, has many examples and goes into a lot of depth.
tbh, you can probably find crab explanations and other pattern explainations from google, but then again some of these explanations are probably not going to be 100% accurate. I would reccomend the book, my understanding of the patterns improved greatly from reading the book.
the full name of the book is, Harmonic Trading: Volume 1: Profiting from the Natural Order of the Financial Markets
if you are able to PM me i might be able to give you advice on getting the book at a "discount"
I do not know if this forum has any restrictions on PM’s though from new users, on some forums if a users postcount is too low he cannot use PM’s.