If I compress something using the 7z commandline tool (7za), use the zip format, and compress any directory, the compression method stays 00 in the file header.
Steps to reproduce:
Compress anything using the 7z commandline tool, and say it you want to have a zip archive.
Open the file with any hex editor, and see the bytes 8 and 9 are 00 00 instead of 00 08.
The default compression method of zip's is deflate, and deflate has the number 8 in zip's. Instead of 00 00, there should be 00 08.