[edawerd]

There are many ACH transaction types (called: SEC cods).

The post I wrote generally applies to PPD SEC codes, which are generally used when debiting a consumer bank account.

The 60-day rule applies to PPD SEC codes.

There's another ACH SEC code called CCD, which can be used when debiting a corporate bank account. For CCD codes, an 'unauthorized' return must be received within 48 hours, instead of the 60-days.

Here's a full list of ACH SEC codes:

http://en.wikipedia.org/wiki/Automated_Clearing_House