Need help with India Cooch-Behar 1/2 rupee coin.

I need help from someone with expertise with India coins to help me identify this India Cooch-Behar silver coin. It is irregular round, 18.8-19.5 mm in size, and weighs 4.75 grams. 

It is clearly a ½  rupee but there are five of them that look pretty similar:  

https://en.numista.com/catalogue/index.php?r=Cooch+1%2F2&ct=coin&im1=&im2=&tb=y&tc=y&cat=y&ru=&ca=3&no=&v=&i=&b=&ie=&u=&a=&dg=&m=1&f=&t=&w=&mt=&g=&se=&d=&c=&wi=&sw=

All 5 of these coins apparently have inscriptions of the ruler on them but I am not able to interpret them.  I feel I can eliminate the earliest one (KM#72) because the script doesn’t match mine. I think also I can eliminate the second one (KM#115) because the reverse doesn’t seem to match. I see little if any  difference between the last three.  There is a small size and weight difference but that may be insignificant.

India › Indian North-Eastern Dynasties › Cooch-Behar, Kingdom of

Issuer Kingdom of Cooch-Behar (Indian North-Eastern Dynasties)

Type Standard circulation coin

Years 1770-1772

Value ½ Rupee

Currency Rupee

Composition Silver

Weight 4.62 g

Diameter 20 mm

Shape Round

Demonetized Yes

Number N#117725

This is a most likely a matam (½ rupee, previously called a deb) of Bhutan. While very interesting coins in themselves, these are modeled on the earlier, much rarer coins of Cooch Behar. There are many varieties. A good source of information is an article on Coinage of Bhutan by Nicholas Rhodes

http://mms.thlib.org/typescripts/0000/0043/1560.pdf ;

Here are some examples in Numista

https://en.numista.com/catalogue/index.php?r=%C2%BD+rupee+bhutan&ct=coin