Hi Scorpion, 

As a new user of the LSAT practice page, you have access to the diagnostic tests. If you'd like to know where your skills are at the moment without time getting into consideration, you can take the Express diagnostics.

If you have already taken your practice tests but you consider the time to complete them is too short, you can edit your test time settings right here: https://www.khanacademy.org/prep/lsat/settings/accommodations

Hope this helps!

So, if you already signed up for an account, and taken the LSAT Express Diagnostics, then you cannot take another untimed Practice LSAT?