US Citizen getting a visa?

Hello. I am currently visiting Taiwan. I went to get a Chinese visa for my trip to Shanghai on the 19th. They said that i couldn't get a Chinese visa here since there is no Chinese embassy in Taiwan. They suggested I visit Hong Kong and get a visa there. I had to change my flight plans to go to Hong Kong on August 8th, hope to go to a travel agent/the visa office, and then get my tourist visa to Shanghai.

But now I'm worried. Looking online, I see lots of agencies that say that they can help getting a visa. But I also see a lot of official descriptions where US Citizens cannot get a Chinese Visa except in the embassy closest to their home state. In my case California.

Can anyone tell me simply if US citizens can get their first Chinese visa in HK, or do I have to do the processing through the LA office somehow?