to my understanding, yeah that is the main difference, but considering i did edutest at a higher grade level i think its natural that i would find it harder, maybe acer also gets harder but i hear that its easier in comparison.
i actually did edutest in yr 9 for yr 10 entry, sorry abt the confusion. i just used the edutest practice papers and grinded them and also looked up question types that i didnt really get e.g. in numerical reasoning i sucked at matrices so i searched up 'matrix questions numerical reasoning' and a bunch of yt results from other exams like the yr 6 selective or job stuff came up and they provided explanations and strategies - this works for the reasoning and math sections. i did hast in yr 7 and 8 so i cant give concrete advice about that because the only acer prac papers available cater to yr 7 and 8 and also this was kind of a long time ago and things could have changed.
huge disclaimer i was in yr 9 2 years ago so there could have been changes (to my knowledge there aren't) but get other people's advice too. good luck!!!