Generally, the text of government official documents is imitated by Song Dynasty No.3, with a paragraph spacing of 28.8kg.. What are the special circumstances? What are the rules for font spacing?

At present, the latest version of the official document format of the party and government organs (GBT 9704-20 12) does not stipulate line spacing, because in many cases, it is necessary to fine-tune the layout through line spacing, and it cannot be adjusted after death. It is only stipulated that "there are generally 22 lines on each side and 28 words on each line, and the specific situation can be adjusted appropriately". Who stipulated the 28.8 kg you mentioned?