The New York state property tax

[Floris]

Here it is;

My question about the system of the property tax in the state of New York (residental)
I quite understand how the property tax system is levied and what purpose it serves
But the only thing I don't understand is the use of the level of assessment. (correct me if I'm wrong)

The New York state tax department wants to keep the level as high as possible so it represents (closely) the market value so the levy is fair enough.
But if the reassessment has ben two years ago the level of assessment can drop to a lower percentage which makes your assessed property less accurate.

This raises two questions for me:
1. Why would anyone bother if his/her level of assessment is lower? Because a lower assessed value of your property will result in a lower tax bill. (or is it just that only the government wants a high level)

2. What differents does it makes if an assessor assesses residental property every year, but you still need a level of assessment to show when your property/neighboorhood/town has been reassessed the last time?
Isn't the assessment of the assessor already enough.
or is it because the United States are quite big to make sure you assess everything every year so they don't assess every year?

Now I'm quite confused myself,

Can you help me out on this level?

Thanks