Are we sure that Surya is something else? to me it always felt Shaurya was mistaken with it. Likely situation is we are re-doing our MRBM, IRBM & ICBM arsenal with better modern technology infused versions, like A1P. A5 itself is 7-8K km, means with 1ton payload it would do 10k easily imo. So ICBM range is not an issue, making our relatively smaller warhead yield to do the desired damage accurately over very long distance is the target.
Rest, about the distance part, that should be attributed to the nuke SSBN subs & SLBM development. A land launched 10k+ km ICBM will never give your distant adversary the chill feeling like what some SLBM would do. New class SSBN with k5 BM suddenly making an appearance in one of oceans will be something very few land based systems can match.
