165 ppi resolution device comes under mdpi or hdpi

I have device Display Resolution of 320*480,3.5 inch. So its diagonal resolution is 165 ppi. So this device comes under mdpi or hdpi?

In multiple support screen document a table shows the category but, ~160 means minimum 160 0r maximum 160.

From the following image I understand,if device has,

   100 ppi - 140 ppi => ldpi
   141 ppi - 190 ppi => mdpi
   191 ppi - 280 ppi => hdpi
   281 ppi - 280 ppi => xhdpi

I want to know my understanding is correct or wrong?

Also What is the meaning of the tilde(~) symbol in the table?

As you can see some density and resolution ranges overlap. On those fuzzy edges, the constructor can choose to make its device appear in one range (mdpi) or the other (ldpi).

Even a custom rom could change this setting, so this is really not dependent on the hardware indeed.