Not every customer care executive will know everything.
As per last 2 months statements I never received fractional RPs.
You can test it yourself with a 199rs purchase
Axis has mentioned 12 RP for every 200 spent, so ideally it is 84 which is what you got
If they had mentioned 6 RP for every 100 spent, then you would have got 90
There is nothing called Ideally here, for every 200 you receive 12 points. If you buy for 300 you get points for on 200. Thats how it works for reward points. For Cashback cards you get exact value.