There is same value between 2 Currency

i have two different currency (USD and IDR).
For stock in hand, i buy with USD and there is no problem with Stock In Hand Currency. It can look at the picture ($200/Ro, 2.978.000.00). USD convert to IDR.

the problem came when i sold my product with IDR and process until purchase invoice.
I try to see my account tree and i’m confused because my Creditors account had same value (between USD and IDR). I think it should convert from IDR to USD.

is there anything missing on my process?..Please advice and tell me where is the problem…

Thank you…