can anyone enlighten me in general what is the approach for calculating provisioning on bad credits?
Furthermore, as far as I know there is a difference if it is from credit risk or accounting perspective?
It depends upon which accounting standards you're using. It's become quite involved these days and I'm not sure to what extent there's uniformity amongst them. IFRS now allows a provision for expected credit losses but how detailed the calculation of it has to be depends on the operating activities of the organisation.
1. Percentage of sales method = a provision for bad debts wherein a certain percentage is multiplied to the net sales for the year
2. Percentage of A/R method = a certain percentage is multiplied to the net realizable value of A/R to arrive in the ending allowance account of bad debts
3. aging method = individual A/R balances are aged to determine w/c accounts are due and not past due