Railroad retiree and RRB-1099=R

TT asks me 2 questions about my RRB-1099-R that I would like to better understand.

1) The first asked about the "Simplified Method" used last year (2019) to calculate the taxable amount.  What is this, why is it asked and how does it make a difference?  

2) The second asks about the "Youngest Retirement Age" I (and again my wife) could have retired and received a pension from our LAST employer if we had not been disabled?  

 

I like to understand the WHY behind the questions and these 2 questions make no sense to me as they relate to tax calculations.  

 

Thanks