(Objective 13-20) The auditor of Ferguson's, Inc., identified two in- ternal controls in the sales and col- lection cycle for testing. In the first control, the computer verifies that a planned sale on account will not exceed the customer's credit limit entered in the accounts receivable master file. In the second control, the accounts receivable clerk matches bills of lading, sales invoic- es, and customer orders before recording in the sales journal. De- scribe how the presence of general controls over software programs and master file changes affects the extent of audit testing of each of these two internal controls.