Well your English comprehension skills are certainly different to mine, Mr Boxcar Overkill.
There are plenty of inconsistencies even if you allow him the luxury of not understanding the difference between a transmitter and receiver - at one point he states the AI function of the computer can only be checked underwater, and then he says he succesfully sync'ed it on the boat deck after changing the battery.
Clearly the police officers also understood it the same way as me since they checked the computer did not work as Watson stated.
They were also unable to verify the part about him alerting others divers on the rope (not a single person backed up Watson's story).
In context, looks to me like he was fumbling around looking for the word "transmitter". In extemporaneous speech, people often temporarily lose the exact word they are looking for, but carry on talking as if they had it.
In this case, there is no transponder, although he used that word anyway. While technically there is a receiver inside the computer, people rarely call their dive computer a receiver. Whether or not it's true, I think he can adequately explain his dive computer comments by saying, "sorry, I meant transmitter instead of receiver."
I think too much is being made of this inconsistency, especially since the police are parading their case out in the open while the defense is holding their cards close to their vest. We don't know what exactly the defense is going to have to say about all of this, but this I don't think it is not as damning as people are making it out to be.
It is very hard to get a conviction for murder based exclusively on inconsistent testimony of the defendant. Especially when he gets a chance to clear it up.
In the grand scheme of things, this is pretty thin evidence to hand a murder charge on. There's no direct witnesses or evidence. The evidence is five years old. A corner's report is not only fairly tepid, it also sets up an alternative theory of an embolism. The victim is a known to be a new diver, unsafe, and prone to panic. The defendant can testify in his own behalf and claim he didn't do it.
And that's the starting point. It only gets better for the defense from there when they start putting on their witnesses and evidence.