The "Allow Dynamic CAL Assigmnet" in the Licence section of the QMC is just for Named User CALs. Dynamic CAL Assignment for DocCALs is done in the properties for each document in the QMC, I believe.
So, you could remove all CAL assignments and enable these features to reissue them dynamically. However, if you are hoping to have a fast turnaround of licence allocation you will be disappointed. The server will only issue licence leases for a minimum of 30 days. If your user doesn't access for this time then the CAL will be re-issued, but you can't shorten this lease - which is intentional to stop customers using Named CALs and DocCALs like Session CALs. (Although you can always revoke the licences maunally...)
So there might be a chance of us running out of licenses if all 95 licenses are used within a month?
Yes, I believe so. If you want a concurrent user model you have to use Session CALs, but they are crazy-expensive and I have yet to see a use-case to justify them. Otherwise, you will need to monitor usage and clean up manually, regularly.