You have not made a case to deviate, if that's what you want to do.
"I have a pendulum impact test manufactured according to ISO standard" does this mean you have purchased an impact tester? Or are you supposed to perform the test and want to change the rules?
What does the ASME code have to say on the subject?
Or, do you want someone to give you a free opinion?
In Tunisia, we apply the ASME codes in the field of oïl and gas. There only Charpy Pendulum impact test according to ISO. ( ISO 148 and ASTM E23 are different to the radiud of the knife).
IS The ASME code section VIII division 1 for example accept the results repaired in accordance with ISO 148-1.