I regularly vist the Oz astro retailer sites (a number of times each week) to keep an eye on pricing. Particularly with regard to eyepieces, filters, etc
My comment/s are based on general observations over many months, Chris.
I also keep a close eye on the Oz-Us exchange rate, through no other reason than I have to broadcast it (on air, on radio) as a requirment of my job as a journalist out of several news bulletins each day.
It's probably reasonable that you ask for specific dates and examples. Do you have some you can toss our way, which you are basing your counter-argument on
Anyway...I recommend anyone who isn't content with the prices being asked by local vendors to shop around. Compare sites. It can be very worthwhile on smaller items such as eyepieces.