Quite simply, no, or at least not in the manner you are asking for. I will edit the code again (if I can) to handle your request to the best of my ability.
The @ character shows because it is a higher level of access than +, and the server (not mIRC), restricts the showing character to the one that is the highest level.
You will see this same thing in your nicklists if a nick has multiple modes assigned to them.
