https://www.epo.org/en/node/online-only-2

I want to enter the European phase. Are the refund instructions I submitted to the EPO as receiving Office also valid in the European phase?

No. The refund instructions that you gave the EPO as RO or as International Authority under the PCT (ISA/IPEA) are only valid during the international phase. Therefore, you must file new refund instructions when you enter the European phase. You can do that with EPO Form 1200E.