Inter- company Inome/expense- Interest

Suppose there are loans between Parent(P) and Subsidiary(S). The following is the interest transaction between P and S:

P – Total Interest Expense – 315
Interest Income from S – 300

S – Interest expense to P – 300
Interest Income from P – 210
Difference 90

The book has charged 90 in profit or loss of S while calculating profit to be distributed to NCI. Should 90 be charged. (i.e. difference of interest of 300 and 210 of subsidiary). I’m asking because both the 300 and 210 relates to parent and in my opinion both should not have impact on profit.