The difficult judgement for Theresa May and her senior ministers on Monday is whether to make a full and final offer for what the United Kingdom is prepared to pay as its divorce bill in the next couple of weeks.
The decision rests on two separate questions.
Firstly, is it a matter of economic life and death whether Brexit talks move on to the next phase - sorting trade and security arrangements - in December or March?
If speed is of the essence, May would offer more now.
For what it’s worth, her Brexit minister David Davis is more relaxed about a delay until March than her Chancellor Philip Hammond.
And the foreign secretary Boris Johnson is religiously obsessed with making sure we don’t pay a cent more than is legally due.
Secondly, can the European Union actually accept a new offer from the UK on how much we think we owe - £40billion versus EU estimates of more than £60billion - when the most powerful country in Europe, Germany, is in political turmoil?
In other words, is there any point making a better divorce offer whenAngela Merkel is focused on her own political survival, and is unlikely to prioritise what for her is the irksome secondary issue of whether the UK is adequately recognising its debts.
May and her Cabinet big-hitters will have a genuine debate on Monday. And they are likely to license May and Davis to offer that £40billion or so.
But it is a potential problem that some EU governments think we should pay much more. It would be consistent with the chaos of the Brexit talks to date if the EU says thanks and they’ll get back to us when Germany has a stable leader.