I have compressed full PowerArchiver x64 portable in my SSD disk, so it is easy for you to reproduce.
Uncompressed size: 176.473.679 bytes.
7-Zip 17.00 Ultra LZMA 128MB fb273 myx=9: 28.330.063 bytes.
PowerArchiver 7z 17.00.69 LZMA Ultra: 29.060.624 bytes.
7-Zip 17.00 Ultra LZMA2 128MB fb273 myx=9: 28.323.572 bytes.
PowerArchiver 17.00.69 7z LZMA2 Ultra: 29.062.095 bytes.
PowerArchiver 17.00.69 7z Optimized Ultra: 41.579.382 bytes.
Take a look at the bad results with the Optimized profile, and also at the equivalent PA implementation, being slightly worse than the one in 7-Zip, meaning that the library used or its parameters, are subobtimal.
By the way, same with PA format, excellent results:
PowerArchiver 17.00.69 pa Extreme Optimize Strong: 27.114.421 bytes.