Faced similar situation today, here is the solution for the problem.
Assign a group to the recipients, add an extra column to the recipients excel which contains the group. Now While importing those recipients by recipient import wizard label it as group. Now in the Task--> recipient add the group instead of individual recipients. That's it.
When ever there is change in Excel containing the recipients list those will be automatically updated in the NSQ recipient list and further that will get updated in Task-->Distribution List as we are using the group here.
I´ve been dealing with recipients imports, and I found that the best configuration for that case is:
1. Create Recipient Groups for tasks
2. In your recipient list relate recipients to Groups , mapping the "Group1" field in Recipient Imports
3. In your recipient list create a field with true value, and map it to "Clear Group List" in Recipient Imports
4. Create an Import Recipient Task, check All recipients and Delete old recipients.
Hope that helps