NAB, Banks and Looming Mortgage Crisis, page-47

"If a company profit goes down by 50%"
Net profit has been consistent with 2017. Its actually jumped up 5%

"does it entitle a CEO for Excessive Paypackage ?" No hence the below:
https://www.abc.net.au/news/2018-09-19/nab-executives-to-get-a-pay-haircut-over-ongoing-misconduct/10281232

"NAB has gone in gutter from being the Biggest Bank of Australia down to Smallest Bank among the top four."
Can you please state your source when you make this statement. As far as I can see based on Market cap CBA has always been the largest of the big four.

"Why did they receive Bonus while NAB gone from being Largest Bank to Smallest Bank ? ? ?"
Even if this has been the case, does it really matter? It would simply mean that the other banks have grown at a faster rate than NAB. It doesnt mean that NAB is being ripped off or that they arent making profit. If CBA had 200M in assets and it went to 250M with a 20% profit and NAB had 200M in assets and went to 230M with a 10% profit would you say that the CEO is doing a horrible job and doesnt deserve a bonus? Horrible logic....