Issues with updating baseline and assigning resource by role (results in duplications of resources)

After changing a resource that has the same assigned role and proceeding to update the baseline the previous resource is still there along with the newly assigned resource.  The total budgeted labor units also increases.  For example:

 

 

Resourece            Role                  Budgeted labor units

Bob                       Plumber             8 hrs

I later find out that Bob is no longer working this activity and Jan will be doing that work.  I want to update the baseline to reflect the change.  I proceed to change the activity and it looks like the following:

 

Resource             Role                   Budgeted Labor Units

Jan                      Plumber               8 hrs

 

After going through all of the steps to update the baseline I see that the planned value labor units shows 12 hrs....After restoring the basline, I  locate the activty that was changed it looks like the following: