The short answer is that if you have a set of mutually exclusive hypotheses, such as a proposition and its negation, then your credences for them should sum to unity. Conditional on MTBI’s assumptions, a 55% credence for T-type does indeed imply a 45% credence for F-type. If I think people will misunderstand me due to connotations, then I need to be more clear when expressing myself, but that doesn’t change my internal beliefs.
The short answer is that if you have a set of mutually exclusive hypotheses, such as a proposition and its negation, then your credences for them should sum to unity. Conditional on MTBI’s assumptions, a 55% credence for T-type does indeed imply a 45% credence for F-type. If I think people will misunderstand me due to connotations, then I need to be more clear when expressing myself, but that doesn’t change my internal beliefs.