Creditworthiness vs Rating

I remember two questions: Which factor is important for a analyst to decide whether 1) Company will be able to pay interest payable? Ans Cash Flow from Operation (CFO) 2) Company will be considered for higher credit rating?(Diverse,multi industry and big coglomerate) Creditworthiness is determined by the credit ratings to some extent ,then why this difference?

I think the ability to pay interest is an important consideration but the default risk is higher than a conglomerate because it has business and systemic risk. A diversified company’s debt exposes the bondholders to less business risk and mostly just systemic risk. I forget exactly but I remember the grade was based on 4 "C"s.