Return Numerical Label For LAST Value Subtracted To Reach Sum Target Value

I am looking for a Formula that can process the following:

The Sum Target Value is variable e.g.; 147
I have two columns of numerical values: Column “A” and Column “B.”
Column “A” Houses the Numerical Labels that I wish to have Returned when the
Sum Target Value is processed /reached - Subtract Sum Target Value as noted
below.

To Subtract Sum Target Value:
Start from LAST non-zero numerical value in Column “B” and Subtract one Cell
value at a time (or Sum up the Column) until the Sum Target Value or nearest
possible Sum BELOW, the Sum Target Value is reached. In this instance, it is
147. I wish to Sum the values in Column “B” to 147 per the above. The
summed values can be below BUT NOT over the Sum Target Value.

Return the Numerical Value that is Offset ONE Cell to the LEFT (Column “A”)
and ONE Row Above LAST value Subtracted (in Column “B”) to reach Sum Target
Value. The Result – Numerical Label should come from Column “A.”

Col “A” Col “B”
2003
2051
2105
21511
22010
22515
23016
23510
24011
24529
25020

Reaching the Sum Target Value of 147 in Column “B” would go up to value 26,
Label 295 in Column “A”, totalling 131 which is below the Sum Target 147 but
including the value of 31 above it, would exceed the Sum Target Value of 147.

The required Result is returned from Column “A” Label 290 which is ONE Cell
to the LEFT (Column “A”) and ONE Row Above LAST value Subtracted (in Column
“B”).