For those of you who are new to WCG and use of the BOINC client, here's an explanation of how credit/points are awarded.
BOINC uses what is referred to as the quorum system. For WCG projects, all of members of the quorum have to complete the same work unit before that WU is validated and credit is awarded. This is to ensure that the WU has undergone enough processing to satisfy the scientists. The size of the quorum varies, depending on the project.
Below is an example of a validated WU. The "granted credit" is calculated by taking the average of the claimed credit results. This explains why your granted credit may be higher or lower than your claimed credit. Your result is the one that's highlighted (see below).
Update: Now that FAAH uses a quorum of 2, granted credit is awarded two ways. The standard BOINC practice is to award the lower of the two claimed credits. If the two claimed credits are similar, then the granted credit will be an average of the two, which was the way credit was awarded when the FAAH quorum was made up of 3 hosts.