How to interpret reported file sizes from dd?

System: iMac M4, Sequoia 15.6 I found various suggestions for quick ways to create a large file for testing purposes. What I don't understand is what dd actually produces. Example: dd if=/dev/urandom of=bar.txt bs=1g count=10 seek=100 Finder window says "bar.txt 118.11 GB" . But the GetInfo window says "size 118,111,600,640 bytes (10.75 GB on disk) " Further, the GetInfo window for "Macintosh HD" seems to agree with the smaller value so far as disk space used vs. free is concerned. I'm guessing that my inexperience with dd means I'm not using bs and seek correctly? If so, what are a set of compatible args to use so the output file has a reliable size reported? As a side note, mkfile 10g fmkfile.txt produces a file that both Finder and GetInfo agree is 10.74 GB.