Winston is 100% correct. Been there, done that with the entire Zodiac line and it just did not work.
You really need to bite the bullet and purchase a product from your vet such as Revolution for cats. I can't believe I was foolish in spending so much money with the store shelf stuff and was actually cheaper buying the vet prescribed drops in the long run.
If you visit your vet now and purchase a 6 month supply, you'll probably only need 1 tube per cat to kill the adults & larvae and will have some left over to kick off the flea season next summer.