Learn English – “was called” vs. “has been called”

I know the basics about past tense vs present perfect tense, but I'm wondering in some situations whether the "connection to the present" (which seems to be a necessity for the present perfect tense) does indeed exist or not, e.g., in the following example from computer programming (where you can "call a function", i.e., execute it):

1. Only use function A if the function B was called before.
2. Only use function A if the function B has been called before.

What's the correct way? Is it different in American English vs. British English?