I can understand that if you have two mobile phones, one from (say) the UK, and one from (say) India, then the price for roaming is likely to be very different between them when you're in a country near one and far from the other. It would seem to make sense that when in Nepal, roaming calls from an Indian mobile would be cheaper than from a UK mobile, as it's much closer to one than the other.
However... If you're a long way from "home" from both mobiles, one might naively assume that the roaming fees would be pretty similar.
On a recent trip from the UK to India, I was changing planes in the Middle East. While there, I turned on a UK mobile, and an Indian mobile, to check for travel updates. The Indian mobile had a basic pay-as-you-go deal, while the UK one had a package to offer lower-than-normal roaming rates. Despite this, and despite being a long way from both the UK and India, my UK phone wanted ~ USD $2/minute for calls and USD $8 for 10MB of data. On the other hand, the Indian mobile offered 100MB of data for free, and calls from USD $0.20/minute.
Why is it that the naive idea isn't right, and when a long way from home, mobile roaming prices vary so much by where you have come from?