I'm fairly sure he 'flipped' the money somehow and kept the profits in the nearly half year he sat on it.
You can picture Gordon Gekko saying, "Ok gang, we've got five mil, what can we do with it in 6 months?"
Trump is just pissed because people started squawking about the money before he was done using it.
As far as the overhead fees he deducted, there are two major/primary questions. The first is, How much did he really raise? He says 6 million, but how do we know it wasn't really 7 or 10 million? We don't know that. How do we know that the 5.6 million that he claims he gave isn't really just half or less than half of the total amount he took in?
Second, What about the simple interest the money must have gained while Trump was "holding" it for us? Where did that money go? Did he keep it? We don't know.
Regardless of any political leanings, because of Trump himself as a person not a politician, and his very evasive and highly reluctant behavior in discussing the very specific details of what happened with the money he collected, this is just screaming for a full audit. This is not partisan. I think any normal person would be at least curious about what happened.
No more "fund raisers" for Trump. I can't see that happening again.