@Christoph-Green-Frog#149845 well, this is due to each banks own implementation frame and time table, for example, bunq likes to wait a bit for connecting with new instant banks in whichever direction, as to make sure it all goes without fault and is a stable connection for all parties concerned, let's call this the good approach, then there are of course banks, mainly in the Netherlands* that have been ready and stable for SCT INST for months now but actually have not activated it yet, because they want to focus on local in-land payments first, so let's call that Dutch Instant payments, so they are actually working with SCT INST, but actually process those payments only with a local CSM** for instant transfers.
Then there are of course the banks in Germany, who completely against the spirit of the banking rules and the EU-wide agreements for instant payments standards decide to make it an option for the users which form of transfer to use which then also leads to confusion and also also them to charge extra for it when it does not cost anything extra at the ECB and CSM facilities. Which again, is against the spirit of the deals.
As for Dutch banks, they do not charge extra but rather hold the opinion that they will gradually replace all old sepa transfers with instant payments in the coming years, so that IS forward thinking, even if it's handicapped by them first introducing their own instant systems, before connecting to SEPA INST later this year.
( *ASN, ING, knab, Rabobank, SNS, Volksbank, BNG, Waterschapsbank etc.
**CSM: Clearing and Settlement Mechanism, a sort of PSP, that is a Payment Service Provider, for banks to handle all their incoming and outgoing cross-banking/inter-banking transactions.)