is it possible my 5 year old english pointer is smart enough to know that scratching his ear will get him a spot on the bed?

He's accustom to sleeping on the bed with us. We'd prefer he sleep on his own dog bed but (I'll admit) we failed to enforce this early on and now he's just used to sleeping with us.

Whenever we finally get fed up and force him to sleep on his own dog bed beside ours (which is usually about once every six weeks) he is fine on it at first. But after a while (sometimes days, sometimes hours) he starts scratching his ear and shaking his head like it hurts.

We give him his flea meds once a month, and I've never seen a flea on him. So I doubt it is that. But whenever he does this scratching, either one of two things happens:

1. I give in and he comes back onto our bed and sleeps fine (not so fine for us).
2. OR... He eventually ends up in the vet costing us hundreds of dollars (not so fine for us). Whenever he goes to the vet, they say its a  yeast infection in his ear. I don't doubt that, but why is it that this ONLY seems to erupt whenever we enforce the "off the bed!" rule?

This happens about once every three to five months. -- ie, three months on the bed - one-to-five nights off the bed followed by a big vet bill.

This has been going on for about three years. His sister always sleeps on her bed with no problems.

Over the course of time we've continued to buy them both new beds and the bed he was on tonight is only 1 month old.

Is it possible that he's on to us? Can he be smart enough to know that if he scratches his ear, we'll let him back on the bed (or maybe it's the result of a neurosis that he's not even aware he's initiating)?

Either way, he works the ear (not always the same ear) until he scratches it bloody with his nails.