The notary must do so within 15 days. As he actually has to walk to the regsitration tax office, and hand over the contracts, he won't do so every day. Once a week the notary will go to the regsitration office.
Each notary is appointed to a certain registration tax office. As they don't want all their notaries to come the same day, the notary will be appointed 2 days of the week (e.g. Tuesday and Friday) when the can bringh his contract and take back the registered ones from the previous visit.
For company contracts he will ask for an urgent regustration, so that he can take the registered contract with. The other contracts he will get back the next time he visits the registration office.
The notary can sent a clerk to the registration office to bring and collect the contracts and pay the registration tax.