A question about using libaacplus encoder audio and checking it with vlc

[abdamon]

I am learning HEAAC recently,and I make some try about it;Here is my problems：
I use libaacplus encode a audio,and check it with vlc;when I check the audio which is already encoded,the version of the audio is AAC+SBR V2;but when I check the audio that is encoding through the code stream,the version of the audio is AAC+SBR;
It is surprise that they are not the same!and i use logs to check what is different when the libaacplus encoding the audio.and the logs shows they are the same.
Could you help to tell me why they are different?thanks very much.