Exterminaters love the "bait stations" because there cheap to buy and most companys like Terminex and Orkin charge almost $100.00 a piece to install them, there cost is about $28.00 a case, and take about 1 min to install with a bulb planter, then charge you every few months to come back and check them.
There going to place them on the outside of the house out far enough away so there behond the drip line of the house.
The termites you have are nesting under the house so the bait stations located out away from the foundation do no good.
Termites are blind and if they have plenty of food in your home there's no need for them to go looking round the house looking for a tiny 2" tube of so called bait 4' from the foundation.
For any hope of getting rid of them in the long run your house really needs to be lifted to get it up off the ground. Even with a liquid treatment and trenching the whole foundation there's going to be spots that are not going to get treated be cause some areas are just going to be to low to get to.
The new chemicals being used travel no more then 10' from point of contact with the soil and when picked up by the workers it's carryed back to the queen for food, once shes gone the nest dies out.
I've inspected 100's of homes with the sentracon system installed, nd had been there for many years and almost always found active termites still in the house.
Where all stupid, just in different subjects.