If Sony's default application has metering modes, but the API does not support metering areas, then Sony has extended the default camera API to expose metering modes through some other path. Likely a custom camera parameter.
If you want to implement such metering modes in your own app, you'll have to figure out how Sony did the extension (one idea is to dump out the whole Camera.Parameters structure, and see if any of the names look promising).
However, anything like this you do will likely only work on that Sony device, and it's not even guaranteed that it'll work on Sony's other devices, unless Sony itself has made some statement about these features and how to use them (and how stable they are).