I've gone back over the OP and the sandboxes, and I've compiled my thoughts for why I'm still voting to disagree with the OP's proposal.
Issue 1 - Destructiveness of the explosion
The first point that I want to bring to attention is that I believe that
the calculation for the explosion of the coast of Whiskey Peak is higher than what was intended. Now, this isn't a point of incredulity in believing that the characters shouldn't be at this tier. It's based on examining the actual destructive effects of the explosion.
I didn't realize it until I reread it but we do actually get a look at the direct aftermath and effect of the explosion. In chapter 114,
we can see Nico Robin coming across the remnants of the wooden ship that Igaram was sailing on and strangely enough it looks like significant portions of it are intact. There's the mast and sail, pieces of the hull, a barrel, and even one of the decoys that Igaram was using.
While the ship was fragmented... this is
far less destructive than an explosion that is
230 Kilotons (Large Town level) should be producing. If you calculate the actual destruction of the ship, it will be far less powerful than the effects an explosion of this series should produce.
I believe this is important to take into consideration because we have precedent for similar situations when it comes to kinetic energy calculations.
If the destructive effects of a kinetic energy feat do not correlate with the calculated value of the kinetic energy, then the results are deemed unreliable. Preference is given to
actual destructiveness as this is regarded as better proof of how much damage an attack can inflict. It's not like the doll decoy or the wooden barrel would be assigned a Large Town level durability rating either for surviving the explosion.
Issue 2 - Inverse-square law
My next point is that even if we granted that the explosion is really as powerful as what has been calculated, that doesn't make it correct to scale Igaram's durability to the
full value of the calc just because he was in the proximity of the explosion and survived it.
The inverse-square law means that intensity drops off with distance as the explosion spreads outward. To give you the idea of how much this could lower the intensity that he'd actually take, I'll give you a rudimentary example calculation. Assuming that the epicenter of the explosion was ten meters away from Igaram, which is plausible given that it's a decently large ship that he's sailing on, and using cross-sectional surface area of 1.1159m^2 for him to account for him being significantly taller than average, the amount of actual energy he's got hit by would be roughly
409.05 Tons (Multi-City Block level). And that's not taking into account the material that could've been between Igaram and the explosive itself dampening the effects, or the fact that we can't say with absolutely certainty that he was hit at all since we don't know his exact location at the time of the explosion and it's plausible that Robin deliberately spared him - there is a lot of ambiguity here as it is never clarified to the reader exactly how Igaram survived. We've just got to go off context that Robin was disloyal to Crocodile. And let's be real, is
Nico Robin so incompetent as an assassin that she would use an explosion that would leave Igaram alive
and with barely a scratch?
So distance is absolutely a factor that would be relevant for Igaram not scaling to the full value. Typically for explosive feats, you need visual evidence of the characters being within point-blank range of the explosion to consider scaling them full to it.
Issue 3 - Scaling issues
Lastly I believe that even if we did grant that the explosion is as powerful as what has been calculated and that we did somehow scale Igaram's durability to the full value, that would contradict the general powerscaling of this early part of One Piece.
Here are the other AP calculations that the relevant characters in this scaling chain for East Blue Saga and Alabasta Saga have:
Usopp and
Babe, AKA Mr. 4 was significantly damaged by explosive balls that have been calculated to be roughly 1460 times weaker than this ship-destroying explosion that Igaram supposedly tanked.
You have characters in the East Blue Saga who have calculations ranging from High 8-C to 8-A but this proposal would make them all High 7-C, effectively ignoring their own individual feats. There are just no support feats at this stage in the manga, for the characters to be this powerful this early on. That's why I think it's an extremely bad idea to make Igaram the foundation stone for the scaling chain of every single East Blue Saga character.
@FinePoint @Vietthai96 @KingTempest As you've all commented on this thread before, I'm hoping that you could give my reasons for disagreeing a read when convenient.