Postal Life Insurance

#1
Recently i came to know about postal life insurance.

The agent mention that using monthly investment plan [ ie. similar to SIP ] the amound got doubled by 10 years.

If this is true the interest rate should be 12-14% and the effective interest rate will be > 20%.....:clap:!!!!!. Tested via https://www.corpbanknet.com/Recurr_deposit_Calc.html

But the post office site mention only about Bonus per Rs1000/-

http://www.indiapost.gov.in/netscape/Sumangal.html
http://maharashtrapost.gov.in/htmldocs/postalinsurance.htm

Can some one explain how this bonus calculations are really working if i am doing monthly installments of Rs 1500 for 10 years.

I want to confirm whether the amound [ 1500 * 12 * 10 = 180000 ] got doubled in 10 years via GramPriya Postal Life Insurance scheme.
 
#3
The Postal Life Insurance Service is a state-run service that
aims to provide people living in the world with easily accessible life insurance and annuities at the lowest possible
premiums, realized as a result of efficient operations. It is intended to help stabilize the economic livelihood of people and secure their welfare.A nonprofit, government-run service.