you sure? i used to have a 8310 and when i brought it there they upgraded it for free. I dont know in other places but here in the philippines they didnt charge me.
Ah ha, there comes the warranty card again. What if you run out of warranty? Here most of them buy phones in grey, which is around $40-60US(approx) cheaper, but doesn't come with the warranty. so that's why even if you have warranty they charge you Rs. 81(approx
The gray market is basically a middlepath between the black market and the white market. You buy phones without warranty, etc and for a much lower price. These phones come imported from other countries(NOT SMUGGLED), all tax and all is paid up, but when it arrives here, some phones are documented missing, and these phones get sold for a lower gray price...