Offset customer and vendor in F110

Hello,

There is an option to offset customer and vendor in F110.

All is defined as required. Up to the moment of proposal everything works.

According to this blog:

https://blogs.sap.com/2014/07/08/offseting-between-vendor-and-customer-balance-via-f110/
Here on the step 2 of proposal - it is red. I need to get to each document and define bank with "Reallocate button".

Could you please help to understand what is wrong in customizing? Why the bank is not defined automatically and allocated automatically if it is assigned in FBZP in the payment method?

E.g. here in the end - she has proposal green immediately:
Ticket of Vendor Payment Clearing with Customer payment in SAP (Video 24) | SAP FICO Tutorial - YouTube

Thank you,

Regards,

Olga