The Spanish example appears to permit submission of invoices up to 4 days after posting.
In Albania and other Balkan countries it looks like they are expected to do this in real-time: they click post, the invoice is copied to the tax office over HTTPS and they receive a response with a serial number to be placed on the printed invoice.
It is not clear what they can do if the API is down, certificate expired, power cuts, etc. Some of the news sites suggest they have been encouraged to participate in this in the hope of joining the EU.
I found some technical specifications for Albania and Montenegro.
It looks like they may be using slightly different procedures depending on whether it is a cash sale, B2C or B2B scenario.