Su, 58 vs. 62 is not that much of a difference. The difference in the weight argument takes prominence when you are talking about 48 tons vs. 58 or 62 tons. (AK vs Arjun vs Leo2). As you can see, a 10 ton difference is a fairly significant one. At that point, you go on and decide on what approach to tank design you want to take. Maybe a much lighter tank does not provide you with enough protection, or a heavier tank is too cumbersome on the battlefield etc. etc.
I think Pakistan and India have problems that are not necessarily with the ability to use such heavy tanks in these regions like the Thar and Rajhastan, rather these problems have more to do with the lack of infrastructure to support such heavy vehicles.
