This is interesting. I was not even aware that WavPak may be used in a DSF container. I converted the downloaded DSF file as it was created from the test link I provided above. This is what Mediainfo shows about it:
Audio
Format : DSD
Format/Info : Direct Stream Digital
Commercial name : DSD256
Format settings : Little
Duration : 6 min 54 s
Bit rate : 22.6 Mb/s
Channel(s) : 2 channels
Channel layout : L R
Sampling rate : 11.3 MHz
Compression mode : Lossless
Stream size : 1.09 GiB (100%)
I performed the conversion using EZ CD Audio Converter that used the maximum sample rate that PCM currently supports:
Audio
Format : FLAC
Format/Info : Free Lossless Audio Codec
Duration : 6 min 54 s
Bit rate mode : Variable
Bit rate : 7 959 kb/s
Channel(s) : 2 channels
Channel layout : L R
Sampling rate : 352.8 kHz
Bit depth : 24 bits
Compression mode : Lossless
Replay gain : -0.91 dB
Replay gain peak : 0.966954
Stream size : 394 MiB (100%)
Writing library : libFLAC 1.3.3 (UTC 2019-08-04)
The sampling rate for the FLAC conversion will never be close to the original test file I downloaded. I cannot tell from Mediainfo that the size difference is in part due to FLAC compression. It is not showing any information related to compression.
Thanks for sharing this detail. Honestly I have not used DSD much at all, so my reason for even getting a DSD512 file was mainly for test purposes when I get my new DAC.