Time is an estimate, and given a certain timestamped receipt, Terri would have to have changed her story about what time she left, wouldn't she? It doesn't work in our math to get there in 12 minutes, and it probably doesn't work in LE's timeline, either. And so, the next time she's interviewed, she'll have to change what time she leaves (remember, that same email says she had to go back for more interviews) in order to make it make sense. We just don't know what that next interview revealed to LE. What we also know is that Andrea saw her at the second FM by around 10 a.m. We know that by 9:45 (per the new timeline from TP, which should have been the old one....:: sigh :: ) Kyron was noted as missing from the group he was supposed to be in, and presumably missing from the school altogether, although LE did say that he was swallowed up by the school.
So, if there is enough time for Terri to drive back to Skyline from the first FM and then back to the second FM to be spotted by Andrea (an amazing circumstance), I'd be willing to consider that as the more likely time Terri (IF SHE DID IT) could have done it.
But ......... wowzers.