The AND logic seems odd to me too, the OR is more what I'm looking for.
The linked post from Ken tells the reason for the AND gate: the signal is active low. So if one of the two goes low, the output has to be low, an AND gate is doing exactly this.
Is a RS485 based solution more robust ?
Definitely, but it's also a lot more work. I agree with Chagrin, that testing the low cost version is worth a try.