That is not logical. When people try & contact DJT they are referred to the proper person, who would have been Cohen for legal matters. SD would never have gotten to DJT for conversation on a this subject or probably any subject, that’s what secretaries are for.
The agreement would have been with Cohen as an ongoing thing for all legal matters of a defined type. Depending on the material in any given time period the charges would have varied. It is very reasonable that the bills were just paid.
Typically, in these matters, anyone who may be at risk has the work done, not the other way around. If it was the other way around, and being this close to the election, Cohen would have asked how to handle it.