Activity Percentage Complete vs Schedule Percentage Complete

 I am working in a construction company and I prepared a cost loaded schedule but I am confused while updating of my schedule.

Schedule Status:         Duration Type = Fixed Duration & Units

                                % Complete Type = Physical

WBS Status:               I defined 4 phases

                                    1 = General Requirements (not cost Loaded)           

                                    2= Design Drawing (not cost Loaded)           

                                    3=Construction Phase (Cost Loaded)

                                    4=Project Close Out (not cost Loaded)

Problem: While updating the Percentage to activities which is under General Requirements or Design Drawing the band of WBS is not showing overall percentage of that WBS.

Inspite WBS of General Requirements or Design Drawing, Construction Phase is showing percentage on its bands & whenever I am giving percentage to Activities (in the column of Activity % Complete) 50% the Schedule % complete showing 100%.

1. How these parameters are working please explain somebody?                    
2. So can somebody tell me how to show percentage on band of these two WBS bands?   
3. Which is the best way to update your schedule ?

Please reply somebody …..i ill be highly obliged

Thanks