Allowance for credit losses (aggregate) vs adjustments

Hi Friends,

I am beginner to a/c. I was exploring the items in IFRS chart-of-accounts and I have doubt in the following. Help me understand for journal entry.

Asset >>>  Financial Asset >>>> Allowance For Credit Losses (Aggregate)  (1.4.5) Cr

vs

Asset >>>> Receivables >>> Adjustments (1.8.4) Cr

For example , 

Assume, Customer was billed for Rs.10000 and so far in 7 months he has paid Rs.7000 and

now , I foresee for that balance from customer Rs,3000 planned for next 3 months equally will not be paid (but I wait for every month end with hope he pays )

If it is not every month end for my  a/c closing, 

Q1) Where should I post my entry in 1.4.5 or 1.8.4 ?

Q2) Please explain if there are differences with this case or with others

Q3) should i wait for such adjustment only at fin-year end  .

Regards

SK