HAINAN - 30 DAY VOA and or 90 CHINA VOA? - Clarification needed.

I hold a US Passport, and I want to fly into Hainan, and from what I can gather I would entitled to a 30 day VOA..no problem right?
However, it seems to suggest that when I arrive at immigration in Hainan, I should ask for a 90 day Chinese Mainland VOA instead if I want to visit family, business or work?
Isn't this an easy way to dodge the paperwork requirements required for a tourist/multiple entry Visa, or have I missed something?
*Footnote...
I have a previous one year multiple entry Chinese entry permit I got travelling in China 5 years China, although I do have some overstays from a SEA country and may be blacklisted..would that present a problem for either the Hainan 30 day VOA,or the 90 day VOA??