Investment in Equity (GL) currency conversion

Hi Experts,

Could you help me in setup and understand the behavior of BPC 10.1 (Classic) Nw for Investment in Equity GL

I am doing legal consolidation ( YTD Model):

One Investment GL in which 100$ posted in 2014.01 with exchange rate 60 so at our group level ( INR) value would be 60,000/- INR

now second entry  ( 300$ ) in month of 2014.03 with exchange rate 61 so our group level ( INR) value should be 300*61=   18300/- INR

But system is showing (100+300)*61=24400.

If i am not wrong value should be 100*60  + 300*61  = 24300/- INR   in 2014.03

but as per system calculation is 24400

pls guide me how to handle with this Investment GL

Thanks,

Sam