It's dangerous to assume that your seeding rate needs to change in terms of seeds per square metre, or plants per acre, or pounds per acre of seed  ( or whatever units you might measure in ).

I  don't know what factors might be at work to make Nick want to lower his rate in whatever part of eastern Australia  he is in.    I'm sure he has  good reasons to do so, and I have to assume that he knows and understands his environment, at least as much as anyone can.

All I can say is "here"  we long ago decided  that lowering the seeding rate  as we widened the row spacing  was  not  required.  Most of us now are on 12 inch rows or thereabouts, compared to the standard  of 7 inch  many years ago.

It all depends...on lots of things, and  we all farm in different environments and conditions.

  To  adapt a stolen phrase,  some are more different than others,  and I'd be the first to acknowledge that  the environment I farm in  might be more "different" than most.

One thing  we had to be aware of, that may or may not apply to anyone else,  was the concentration of granular fertiliser  in less rows. I think it led to better fertiliser utilisation for us, but in some cases led to fertiliser toxicity, especially if using a Urea mix down the tube.

All that really means is types of  fertiliser and placement became a bigger issue than it had been previously.