This is one of those stupid (yes, I said it!) decisions that companies make with little thought to the end user and then double down by refusing to listen to their customers when the "feature" is problematic.

At least give users the *option* to clear the field - however, I'd say in most cases that a user changes this field because a service got booked to the wrong account.  The description and rate would remain the same - I just need to book this under a different product/service so that the accounting works for my reporting.

Please raise this as a potential item in an upcoming sprint for them to implement or repurpose this feature.