A/R EFT Setup/Process Questions

With regards to the setup and processing options for A/R EFT - I have the following questions:

1) Is there any way of creating a "minimum threshhold" for EFT generation? I.E. any debit balances < a given $ amount get ignored?

2) Credit Balances: it would appear that the EFT process will pick up any credit balances for EFT customers and create a "credit EFT" transaction - whereby the customer's account will be credited (as opposed to being debited). Is there any way to turn this off?

Appreciate everyone's time here - thanks in advance for any feedback.