Some facts i have learned so far from sayare and others:-
1.Agni 3 reached 800km while Agni 5 reached 600kms , it means Agni 5 which is a completely new and technologically better missile can easily reach 800km and even higher.
2,500km is 4 times higher than 600km, just guess what will be it's maximum range when tested to its full range ! although Chander was talking about ASAT capabilities of Agni 5 with an angle of 70-90 degree, Chander has willfully added some ambiguity to his statement.
2. .See the post #1016 of sayare, it says Agni 5 was tested with 60 degree to 70 or 75 degree of angle, testing it with an angle of 45 degree can dramatically increase its range.
3. Modern missiles do not follow a pure ballistic trajectory,how can you call a missile having MIRVs pure ballistic when you can re-target its aim.
So sayare is right. Agni 5 can go 8-9,000 km easily and with some advancements it will definitely reach 12-13,000kms.