The word "pro" is generally regarded as a universal word, and the word "new" is used for service. Let's get rid of pollution and start over. As for pronunciation, interchangeable words are generally read according to the pronunciation of the words passed. So it is more appropriate to read "Xin" than "Qin". As for your "awkward reading", this is actually a false proposition. This passage was written in the pre-Qin period. The pronunciation of Chinese more than 2000 years ago is very different from that of Mandarin today. The current phonological standards can no longer be used to measure the fluency of words in the past. Let me give you a better example: many Tang poems are pronounced in Mandarin without rhyme, not to mention pre-Qin poems, not rhyming poems. I don't know if I have answered your confusion.