Consuming Dry San pedro in grams

[Fantasian]

I've been reading alot of the posts about consuming San Pedro and people are confusing me.
Firstly Assuming Erowid is valid then these are the dosages of Mescaline

Oral Mescaline Dosages
Threshold 100 mg
Light 100 - 200 mg
Common 200 - 300 mg
Strong 300 - 500 mg
Heavy 500 - 700 mg

If this is true taking into account that the mescaline content of a San Pedro cactus can be anywhere from 0.5% - 2% again according to Erowid.

Doesnt that mean that 20g of Dry San Pedro could quite easily be a good experience. Lets say the cactus available is 1%, 1% of 20g is 200mg. This is just into the common Mescaline dosage. Im confused as I have read numerous posts claiming at least 50g of dry san pedro must be consumed.

Sorry if this offends anyone who has previously posted differant i am just very confused.