A chunk of delayed bags make it the next day - this is often when ground handling just ran out of time and therefore can assure the bags would be on the next service. The next chunk seems to be 3 to 4 days in Europe, it appears to take a day or two longer in USA for some reason. I would guestimate than two thirds of delayed bags are in the this group particularly if there are no connections (though you've effectively added two in terms of Houston and Toronto). The last third or so can be 1 week, 2 weeks sort of area.

WorldTracer is a batch system and doesn't have a full dialogue with couriers. So while it's important that contact details are updated, you can't rely on the data presented in terms of where your bags are. My suspicion is that they were given by BOS handling to a courier company and sent to Houston, now they will be returned to BOS for retransmission to Toronto. If they have not surfaced at 21 days you need to claim for their total loss, though the bags may still arrive after that point.