For a defensive-oriented Pokemon, why is it that the leftover 4 EVs is placed in the remaining defensive stat? For example, the analysis page for Skarmory has it using 4 SpD for the physically Def set while the SpD set uses 4 Def. Since the 4 EVs wouldn't really make a difference in whether a hit will KO or not, wouldn't it be better to just put it in Spe where the difference of 1 point might allow you to Roost or Taunt opposing mons who run 0 Spe?
(Offensive mons normally place it in HP / Def / SpD as it really doesn't matter unless it's a mixed attacker)
It is supposedly done to reduce residual damage from stuff like Stealth Rock and spikes due to the HP stat sometimes being divisible, but often the 4 EVs are placed in a defensive stat other than HP arbitrarily. These are the rules you should really go for before consideration of LO/leftovers numbers:
- Not divisible by 2 for any Pokemon 4x weak to SR
- Not divisible by 4 for any grounded Pokemon barring Volcarona and Magic Guard users and for un-grounded Pokemon 2x weak to Stealth Rock
- Not divisible by 8 for any un-grounded Pokemon which are neutral to Stealth Rock
- Not divisible by 16 for any non-grounded Pokemon which 2x resist Stealth Rock
- Not divisible by 32 for any non-grounded Pokemon which 4x resist Stealth Rock
Of course there are exceptions with Pokemon such as Gliscor, Poison Heal Breloom, Sub+pinch berry users, LO users and a handful of Lefties users, Belly Drum users, Regenerator users etc., where IVs may also need modification or where having a HP stat divisible by one of the above denominators is acceptable, but generally speaking this is what you need to go for
