The 6:05 may have been a set up and that didn't work on the first trip. He did something at 6:25 that involved "data". Purely speculation, the 6:34 could have been practice for the 4 year old to call his phone. The oven timer set to go off with a "do it again when the bell rings" would be the simplest way to "spoof" that call. No equipment necessary. MOO
I am now thinking about this call (6:05). He must have had his cell call forwarded to vm and not realized it. What is a bit funny though is he didn't go into HT until 6:21. If this was supposed to be a spoofed call he would have had to leave the house at 6:00. He would have known what time the call was to be made...so he could have just come home without going to HT if it didn't ring. He would have been driving around for awhile. Also the neighbour did not notice the garage door open at 6:00. Conclusion...not sure it was a spoofed call that failed. Maybe a test call....