I recently got shrooms (Jedi Mindfuck) for the first time only to learn they were on the low end of potency. I tried one with almost no noticeable effects. A friend told me to try more than one and to blend it and at it to a peanut butter sandwich. So I did 4 shrooms. I'll let you guys know later how it went.
The reason for people saying that is individual ones are different sizes and the concentration does vary a little bit but less than the size variation. Grinding them into powder and making weighted potions achieves a lot more control over your dose and if you are getting into tracking how much you take this is very helpful. Never stopped me munching them dry outta bag on occasion though.