LM does not immediately update calculations every time a change is made. (If it did, LM would run slow on some computers.)
LM always makes sure ALL calculations are up to date before any report is issued. OR when you enter or exit the program. 
At anytime you can refresh/update calculations by clicking the 'Calculator' button or pressing F2.

Try it out....
1. Pull up a scorecard and change the course
2. Close the card.
3. Look carefully you will notice the "calculator" button is flashing..this means LM knows it needs at sometime to update calculations.  Click the calculator or press F2 to immediately recalc..see the handicaps change.