How to Make Green Tea (says 175 is typical excepting the lower temp gyuokuro)
Steeping Green Tea | Tea Trekker
The second link also details Chinese green teas and you can clearly see that they recommend hotter temperatures for those (sometimes by as much as ten degrees!).
Both links mention that you should play around within five to ten degrees or so of the recommended temps based on the types of tea and harvest time and desired flavors. You can also play somewhat with the amount of leaf depending on preferred tea strength. It is slightly individual.
Here is a more general steeping guide for tea:
Steeping Tea | Tea Trekker
Here is a little primer that describes the various "boils" as the Chinese define them:
Boiling Water for Tea: Bubbles and Steam | Mighty Leaf
It seems to indicate that it is traditional for the Chinese to take their tea off of the heat and apply it to the tea leaves as SOON as it reaches the desired stage in the boil and NOT to let it "boil and cool." Probably not a huge issue of course, but hey, if they've done it for centuries this way, there must be a good reasoning behind it.