I don't like the classification systemas too much myself but they do serve a purpose. E.g. in a selection process to make a decision or to justify an expensive code inspection etc. In defense of it I can say I provided a summary, of course everything is specified in detail;) For example "catastrophic" is described as:

• Loss of life, life‐threatening or permanently disabling injury or occupational illness
• Loss of an interfacing manned flight system
• Severe detrimental environmental effects
• Loss of launch site facilities
• Loss of system

So I think both standards are equally (un)clear;)