You've already listed most of the differences, they use a different set of wheels, give it comfort grip bars, and a new sticker, and it's an entirely different mower.
You see the particular wording of the sticker has a major effect on overall performance and durability, infarct swapping the stickers over will change the way your mowers work!!! :P
Really it's just an easy way to create a large range of mowers at slightly different price brackets, the same budget mower gets some ball bearings in the wheels, an adjustable vent catcher, and comfort bars, and becomes mid range, slightly higher price, new name.
Then they give it a slightly different engine, and it's premium, add an extra piece of metal, and chuck in a mulch plug, and its premium mulching, and for the real top end, give it a nicer engine, on an alloy base.
Then they might give you one with ball wheels but flat handles, and call it a by-victa, ad you have yet another one.
Makes the customer feel like there's a great variety to chose form, and that you are walking away with something suited to you, while allowing a good level of market infiltration, and creating enough models to have many victa's per bunnings.
Then on top of that, there's the need to keep looking like they have something new, like the Mustang GTS of the mid 80's, it literally is a Vortex, but they had already been using the name Vortex for a while, and the old Mustang GTS looked a little different, so swap the stickers, and the Mustang has been reborn, and that old vortex thing has moved on!!!
