illustrates this point:

BYU is #30 in FPI
They are also #4 in FPI's strength of record, which is basically a record vs. strength of schedule metric (and is most similar to what the former BCS computer rankings would have looked like)
They are #21 in Net Efficiency (which is a significant drop from last week when they were borderline top-10).

So if they are #21 in efficiency and #4 in strength of record, why on earth are they #30 overall? If "this year's" performance was all that was used to calculate FPI, it would stand to reason that BYU would be in the 10-15 range (that's a guess based on the average between 4 and 21). So the only explanation I can come up with as to why they are clear down at #30 is because FPI is still incorporating prior seasons' results into their algorithm (which they do because it has been shown overall to improve prediction accuracy - which is all these metrics are really trying to do).