I looked at the proposal, and I'm favoring High 3-A for the Herald Tiers unless they have a mechanism for anything higher than High 3-A aka the God Heralds [like Thor/Hulk/Heracles]. Thor is a unique case because he not only is one of the Herald few characters who has multiple relatively consistent Tier 1 feats at his peak. However, as others have mentioned he isn't a good basis for scaling because he is Skyfather or higher. Thor's God Blasts come from his divine energy, and his true power. Also, he has other feats indicates he's above Surfer at his "Peak" such as injuring Celestials, defeating Galactus with a God Blast, there is another pretty damning piece of evidence. Silver Surfer is weaker than Mephisto as his page notes. Mephisto while a "
barely a shadow of his former self" easily injures Silver Surfer. In another instance while outside of his realm, he was still
beyond the Surfer, and even with "
his field of Satanic force fading" he was weaker than him.
In contrast Thor
was able to fight evenly against Mephisto in his own realm. This is mostly from stuff currently on their pages, but we have multiple statements putting Thor beyond Silver Surfer, including Thor being able to fight characters beyond Norrin, and an explicit statement saying that Thor is vastly stronger than Norrin at his peak, and
the Surfer is only a flea in comparison.
Using that scan to support 1-A Heralds doesn't make sense because of how contradictory it is. Silver Surfer is supposedly on the same level of Thanos above Thor. However, Thanos usually beats them both or is portrayed as somewhat stronger. I don't think there are many comics that say Surfer >>> Thor, though what is the source because that looks old.
For the mid level Heralds, is the High 3-A proposal including all Heralds, or just the ones currently Low 1-C? I'm not sure where 4-B comes from, as far as I can see from the pages there are only a few Tier 4 calcs. The lowest calc above the Hulk's 5-B is 4-A.