How to relate Material Cost to Earned Value Cost

Hi,

Currently I'm working on a Master Work Program using the Resources Dictionary where all the completion are based on the quantity used. However, when I do the Earned Value Cost (EVC) report, I noticed the EVC is zero due to the Performance % Complete is not inserted with any value. The problem here is, when I insert the Performance % Complete to 100%, the EVC become higher higher than my Actual Material Cost. I put the activitiy completion type as Unit Type, but I cannot key in any value to the Performance % Complete. When I change to Physical Type of completion, the Performance % Complete become 100% and the EVC suddenly jump up exceeding the Actual Material Cost.

Hopefully someone can suggest how to overcome this matter.

Thanks in advance.

Regards,