Should I do LOD III questions from arun sharma?

Its up to you, LOD 2 are though sufficient but if you want some extra practice you can go for it

I think you should probably focus on topic/sectional tests now to build speed and look at LOD III for the topics where you feel you need more practice

u should definitely do LOD 3 i would say as it contains much of a aptitutde thinking whereas there area so much direct questions till LOD 2 ,and cat twists questions which require aptitude..so it will be good for u if u practice that kind of questions ...also lod 3 is a bit harder than original cat lvl but it will help u find patterns and think differently ..so targeting 99%ile..u should do that too