When checking for a Pokemon's IV, there is a selection: is the Pokemon powered up before?
Why and how does it matter?
Is it true that because if we never powered it before, then the Pokemon can only be at level that is "not half level"? That is, it can be only level 20, 21, 22, and so forth, and cannot be level 20.5?
So in that case, if in doubt, we can choose "it is powered before", because if we power it ourselves, then the level can be 20, 20.5, or anything, and therefore, be able to match for all possible results. Is that true?