Calculating days required for an ongoing task

Eg: For a 4 day task, 50% should be completed on day2. if it takes 3 days to complete 50%, then it takes 3 days to complete the remaining work assuming the pace of work is same.
Then apply the following formula for projection calculation:
Projection (Days Required) = IIf([Physical % Complete]>0 And [Physical % Complete]<100,((100-[physical>

Planned percent complete calculation in MPP

Create a Text field. Apply the following formula to calculate Planned % Complete:
str(IIf([Status Date]<[Start],"0",IIf([Status Date]>[Finish],"1",ProjDateDiff([Start],[Status Date])/[Duration]))*100)+"%"
Note: Above formula may not work properly at summary task level.

Planned percent complete vs percent complete in MS Project

Following URLs are the few pointers on this topic
1. http://www.msprojectblog.com/References/Celeris%20What%20Percent%20Complete%20Shoud%20I%20be.pdf

2. http://www.gantthead.com/discussions/discussionsTopicContainer.cfm?ID=5850

3. http://www.microsoft.com/office/community/en-us/default.mspx?query=planned+percent+complete&dg=microsoft.public.project&cat=en-us-microsoftproject&lang=en&cr=US&pt=a1d023a3-f612-4da2-acb8-fda8f850d645&catlist=&dglist=&ptlist=&exp=&sloc=en-us (% complete for a summary bar)