Note that it's 10% off the difference, so:
$46.99 Kmart Voyager
$24.83 BigW Voyager
-------
$22.16 Difference
$2.22 10% of difference
$24.83 Kmart Price Matched Price
-$2.22 Kmart Extra 10%
-------
$22.61 Final Price
Let's just bring the Big W Catalog to Kmart
Also, it probably pays to grab any Voyager you can at that price as you can use it later as fodder to refund BACK to Target, BigW or Myer (the 3 retailers that don't individually SKU) in exchange for the full price Voyager you want.