Current Attempt in Progress Sheridan, Inc produces several models of clocks. An outside supplier has offered to produce the commercial clocks for Sheridan for $480 each. Sheridan needs 1,300 clocks annually, Sheridan has provided the following unit costs for its commercial clocks: Prepare an incremental analysis which shows the effect of the make-or-buy decision. (Enter negative amounts using either a negative sign preceding the number e.g. -45 or parentheses e.3. (45).)