Script to add column based on historical data

I've been trying to add automatic column with py script, but without a success. So the idea is to lets say i have a table like below:

Default Table

And the idea is to create a additional column which tells us a current situation of A or B value over time, so basically something like this: ( let's say that 7-th month data is updated)

Table with new column

Did anyone took similar approach to something like above? Looking for a suggestions & approach ideas or some solutions to problem above. A & B columns could also be like A (as value) and B as value category.


Thanks in advance!!