This is easily misconstrued. He was paid more for the first movie but it doesn't say how much more. Then they came back with an offer for the sequel that was similar to that of supporting actors, below his caliber/role. The article seems structured so you read between the lines and assume Howard was paid some insane sum then balked when he was brought down to earth. While that may be the case, there's still plenty of room in the wording that allows Howard to make little bit more (since he signed up early, it seems reasonable) and then faced an insulting figure for the sequel. Any of the gossip of being difficult on set or other details that are mentioned but can't be confirmed could easily be something included afterward to sway opinion. The only thing that's likely, imo, is that Howard wasn't in the sequel due to a pay dispute.