Thanks very much. Follow-up questions. The due date for submitting the additional fees is 1 month from the date of mailing of the invitation.
(1) Is the due date rigidly enforced or can you pay the equivalent of an extension fee to buy time (I know the EPO has this subtle distinction between "non extendable" due date but "eligible for further processing" for some responses, which means effectively pay a fee and you get more time)?
(2) If you pay the protest fee, do the arguments ("reasoned statement") need to be submitted at that time, or can it be submitted after (if so, what is the time allotted).
The point is that the due date is 1 week away and I'm tied up with another urgent case, so I don't have time to prepare detailed arguments for a protest.
I didn't find any answers in the PCT rules.