Each time you sub a golfer, the program does not immediately update the Handicap for the course conversion...click the Calculator button to "immediately" update calculations. 
LM will update calculations when it must...for example if you try to print a report, move to another event, etc.

It is also important to note...only subs who are playing that night will have a "converted" handicap.

For example:

Assume Team #1 is playing course A with slope 80.
Assume Team #2 is playing course B with slope 100.
Assume Team #3 is playing course C with slope 130.
Assume Team #4 is playing course D with slope 150.

If you sub Andy on team #1 his Final Handicap = Handicap x (80 / 113) 
If you sub Bob on team #2 his Final Handicap = Handicap x (100 / 113) 
If you sub Charles on team #3 his Final Handicap = Handicap x (130 / 113) 
If you sub Dean on team #4 his Final Handicap = Handicap x (150 / 113) 

If Tom is not subbing on any team his Final Handicap = Handicap x (Slope / 113)
It is not known which course he will play and what his handicap will be.  So in essence any golfer that is not subbing has an "Unknown" final handicap.

For more information, please refer to Making Real/Human Substitutions  and Making Ghost Substitutes